CN100502054C - Semiconductor device manufacture method - Google Patents

Abstract

Thin-film semiconductor devices such as TFTs (thin-film transistors) and methods of fabricating the same. TFTs are formed on an insulating substrate. First, a substantially amorphous semiconductor coating is formed on the substrate. A protective coating transparent to laser radiation is formed on the semiconductor coating. The laminate is irradiated with laser radiation to improve the crystallinity of the semiconductor coating. Then, the protective coating is removed to expose the surface of the semiconductor coating. A coating for forming a gate-insulating film is formed. Subsequently, gate electrodes are formed. Another method relates to fabrication of semiconductor devices such as TFTs on an insulating substrate. After forming a first coating consisting mainly of aluminum nitride, a second coating consisting principally of silicon oxide is formed. Semiconductor devices such as TFTs or semiconductor circuits are built on the second coating serving as a base layer.

Description

The manufacture method of semiconductor device

The application is dividing an application of the Chinese patent application that is entitled as " semiconductor device and forming method thereof " 93109877.7 submitted on July 6th, 1993.

Invention field

The present invention relates under the low temperature, be low to moderate 450 ℃ or lower temperature, make the process of insulated gate semiconductor device, also relate to, make the method for the integrated circuit (IC) of the described device that includes high integration with high finished product rate.The present invention relates to semiconductor device, further relate to the semiconductor device of high reliability with above-mentioned technology manufacturing.According to semiconductor device of the present invention, be applicable to, for example, active array drives LCD, image sensor drive circuit etc., and the thin-film transistor that is used for SOI integrated circuit and general semiconductor integrated circuit (for example, microprocessor, microcontroller, microcomputer, semiconductor memory etc.).

Background technology

Recently, people are devoted to research make insulated gate semiconductor device (MOSFETS) on dielectric substrate.This have the device advantage of semiconductor integrated circuit to be the energy high-speed driving circuit on dielectric substrate.With speed mainly by being present in the stray capacitance that electric capacity causes between interconnection line and the substrate and restricted conventional semiconducter IC is compared, this novel semi-conductor integrated circuit can not run into such stray capacitance.To the described MOSFET of film active layer be arranged on the dielectric substrate, be labeled as thin-film transistor (TFT).This TFT also may appear in the conventional semiconducter IC.For example be used as the load transistor of SRAM.

Recently, require on the substrate of printing opacity, to make semiconducter IC, for example resemble the drive circuit in the optics of LCD and image sensor and so on.TFT also is used in such application.But wherein used circuit will form on large tracts of land.So this technical process will be carried out under lower temperature.And when the special semiconducter IC of needs was connected to the device line end that a plurality of terminations are arranged on dielectric substrate, just suggestion formed the whole semiconducter IC of monolithic on same dielectric substrate, or it is just extremely brilliant to form its monolithic at least.

Usually, making TFT will be with amorphous, half amorphous, or the semiconductive thin film of crystallite anneals in 450 ℃ to 1200 ℃ temperature ranges, to be improved crystallinity and very a kind of crystalline membrane of high mobility is arranged.TFT comprises the amorphous TFT that utilizes amorphous material to use semiconductive thin film, and this TFT is obsolete, because the mobility that TFT reached is low to moderate 5cm ²/ VS, in addition lower, and generally this mobility drops to about 1cm ²/ VS or lower numerical value.Because of amorphous TFT operating rate is low, and limits and to be used in N-ditch type TFT, so if adopt amorphous TFT just by limit in very narrow range of application.So these TFT will add fast annealing in above-mentioned temperature range, to obtain 5cm ²/ VS or higher mobility value.Have only after the annealing, these TFT could make P-ditch TFT (PTFT).

But aforesaid heat treatment but has strict restriction to used backing material.So-called high-temperature process comprises temperature is heated to 900 to the highest 1200 ℃ step, make the heat oxide film of high-quality can be used as gate medium, thereby, the thing that should select that can be used for such high-temperature process has been exactly the expensive substrate of image-stone English, sapphire and spinelle and so on, and these expensive materials also are difficult to obtain large-area substrate.

Compare with the high-temperature process situation, various backing materials but can be selected to K cryogenic treatment technology, carry out K cryogenic treatment in temperature is no more than 450 to 750 ℃ of scopes.Yet K cryogenic treatment is wanted long term annealing, because thermal impact, thereby can cause the infringement of substrate distortion and contraction.

In addition, also obtain to have good crystallinity by the thick insulator film being added between Semiconductor substrate and the device with isolation of semiconductor substrate and device, realize forming on the insulating surface MISFET as the element that uses single crystal semiconductor, promptly insulated gate semiconductor device is extremely difficult.Therefore, non-single crystal semiconductor promptly is not that a kind of crystal semiconductor of single crystal semiconductor usually is used for MISFET.

Non-single crystal semiconductor contains high density of defects, earlier general and a certain element, and as hydrogen, in fact neutralization becomes the zero defect attitude.For example implementing neutralization by oxidation handles.Hydrogen and semiconductor element, very weak usually as the atomic bond between the silicon, can break at an easy rate greater than tens ℃ heat energy and cause the decomposition of last gained compound just apply.So when long-time making alive or electric current, because semiconductor local heating, hydrogen is subject to desorb.This phenomenon causes characteristic of semiconductor to degenerate significantly.

Summary of the invention

Inspiration according to above-mentioned situation has proposed the present invention, therefore the purpose of this invention is to provide a kind of processing method, and temperature is not higher than 450 ℃, and backing material is unrestricted, and does not have deformation to shrink problem.Another object of the present invention provides a kind of semiconductor device of this spline structure, can discharge the heat that is produced rapidly during use, and a kind of method of making this device also is provided.

The 1st embodiment of the present invention provides a kind of thin-film semiconductor device, this device comprises on it that preparation has the substrate of film, this film comprises the aluminium nitride as main member, semiconductive thin film directly or indirectly is set on it, comprise the silicon as main member, with and go up the wiring of being made by materials such as metal and semiconductors also directly or indirectly be set.

The present invention also provides a kind of manufacturing to have the method for the thin-film semiconductor device of said structure.Thereby, the 2nd embodiment of the present invention provides a kind of method, this method comprises a kind of film that contains aluminium nitride of formation, as main member, directly or indirectly form the semiconductor film that comprises silicon thereon, as main member, and the also direct or indirect thereon wiring that is provided with by metal and semiconductor and so on material.

Aluminium nitride is good heat conductor, and is suitable for use in the place that needs light transmission, because it has optical energy gap 6.2ev, thereby transparent to visible light and black light.Aluminium nitride film can be by sedimentation, such as sputtering method, and reactive sputtering, and form from MOCVD (metal one organic-matter chemical vapour deposition) method.For obtain nitrogenize companion film with reactive sputtering, this technology is preferably under the nitrogen atmosphere, adopts the aluminium target to realize.According to purpose of the present invention, for reaching enough heat emissions of aluminium nitride film, the better thickness of aluminium nitride film of institute's deposit is 100 to 5000 Aluminium nitride film is 5000

Or thicker difficult realization, because the film of institute's deposit easily comes off.

The aluminium nitride film of Huo Deing is brought into play a kind of barrier effect like this, keeps out movable ion, as the migration of sodium ion.So this film can protect semiconductor device to avoid the infringement of this movable ion.

As long as the thermal conductivity of aluminium nitride film is without prejudice, by desirable proportioning, this film needn't nitrogenous and aluminium, and general, the scope of preferred aluminium and nitrogenize ratio (aluminium/nitrogen) is 0.9 to 1.4, and the thermal conductivity of this film is with 0.6w/cmk or higher for well.This heat conductivity value can have been compared with the 2w/cmk of monocrystalline aluminium nitride.

The tension force of this film can be controlled by the component ratio that changes nitrogen and aluminium the most rightly.Also can dope micro-boron, silicon, carbon, oxygen or the like and come suitable proof stress.This film comprises aluminium nitride, as main member, can be crystallization or amorphous.

Generally, introduce the diamond-type material, such as polycrystalline diamond films, hard carbon films, or diamond-like carbon film can be realized high heat conductance.According to the present invention, when small size, a kind of like this material in device, can be considered, but can not obtain satisfied effect, because do not have bonding closely between diamond-type material and the silica material.Silicon nitride film usually is used for semiconductor technology, as barrier layer and passivation layer, and because thermal conductivity is low, is unsuitable for this.Estimated well-known each film characteristics, its result is incorporated into down so that relatively for this reason:

AIN?1) DLC?2) SnO ₂?3) SiNx?4)

Adhesiveness 5) zero △ 00

Optical transparency zero △ 00

Mechanical strength 00 △ zero

Thermal conductivity 000 △ or *

Thermal resistance zero △ △ zero

The effect zero △ △ zero that stops sodium

Note:

1) AIN: aluminium nitride

2) DLC: diamond-like-carbon

3) SnO ₂: tin oxide, and

4) SiNx: silicon nitride

5) " adhesiveness " means the adhesive power with silica.Each symbol zero of assessment, △ with *, expression " well " " good " and " poor " respectively.

With regard to device of the present invention, on the semiconductor film of the transfer of heat that metal or semiconductor wires (as grating routing etc.) produce below it (for example active layer etc.), and after semiconductor film added electric current, the heat that self produces also was applied to this.So semiconductor film can be heated to higher temperature, yet these heats can promptly be transferred to the aluminium nitride film that is provided with under the semiconductor film, and have prevented to take place on the semiconductor film heat accumulation.Like this, contained that wiring and semiconductor film temperature rise, and avoided hydrogen by desorb.

In the present invention, it is not best semiconductor film directly being deposited on the aluminium nitride.If semiconductor film directly is deposited on the aluminium nitride, bonding force deficiency not only, and caused harmful effect for the electrical characteristics of semiconductor film.Therefore, one deck preferably will be set between semiconductor film and aluminium nitride film can relaxed stress, and the effective material membrane of suitable chemical property is arranged again.

In other words, on aluminium nitride, can form one deck silicon nitride film, and can also form one deck silicon oxide film on it.According to device of the present invention, grid contact by single element, such as silicon (comprising a kind of doping that can improve conductivity) aluminium, tantalum, chromium, tungsten and molybdenum, or are made up of its alloy or plural layers.And, as the being seen example narration in back, also its surface can be given oxidation.Aluminium nitride can be used as etching retaining layer really, because in original process for fabrication of semiconductor device, any lithographic method that is commonly used to etching oxidation silicon, silicon, aluminium etc. can etching oxidation aluminium.

According to method of the present invention, its feature also is, is not by the conventional treatment under the heat balance form, but uses high light, its irradiation face is improved the degree of crystallinity of this semiconductor film as the high light of pulse laser beam or equivalence.Owing to adopted this method, the maximum temperature that can understand this method depends on the anneal temperature of this step process of the temperature of this step rather than semiconductor film, that is, do not depend on temperature such as hydrogenization annealing and gate medium annealing steps.So the used substrate of device of the present invention can be selected from wider material ranges.In more detail, soda-lime glass or alkali-free glass (for example 7059 of Corning Incorporated ^#Glass), these it has been generally acknowledged that the glass that should not be used to do the TFT substrate because softening point is low, and warp is to being used for assembling TFT after the suitable processing of these glass dos.

According to method of the present invention, be included in and form semiconductor film on the insulator substrates, on described semiconductor film, form the transmissive laser beam or be equivalent to the film of the high light of laser beam, make pulse laser beam or be equivalent to the described rete of high light irradiation of laser beam, thereby improve the degree of crystallinity of this semiconductor film; Remove the described film of described transmissive laser beam or equivalent high light, expose the semiconductor film table; On described semiconductor film, form a grid insulating film;

On described gate insulating film, form wiring or gate contact zone again, by injecting the process with ion doping such as ion irradiation, ion, with wiring or gate contact zone is mask, with self aligned mode impurity is introduced described semiconductor film, and after the introducing step, be mask with wiring or gate contact zone, again with pulse laser beam or equivalent high light, the described semiconductor film of irradiation, thus the crystallinity of the semiconductor film of once being damaged in the step of impurity element is introduced in recovery.Latter two steps can be gone into the laser doping method that (referring to, the flat 4-100479 of Japanese patent application No. for example) application discloses by the present invention and be substituted.In the present invention, as the material of gate contact zone and interconnection line, be preferably the metal material of low-resistivity, as aluminium.The used pulse laser beam of the present invention preferably produces spontaneous emission ultraviolet laser device, for example uses KrF, ArF, and XeCL and XeF gas are as excimer.Best, the insulator film material that is produced between described insulator substrates and the described semiconductor film is selected from silicon nitride, aluminium oxide and aluminium nitride, and perhaps these and the tunic that becomes of silicon oxide film combination, oxide-film is arranged between dielectric substrate and the semiconductor film.This silicon oxide film thickness of making is 300 to 3000

, and thickness is from 500-1500

Better.The insulating film material of making is selected from silicon nitride, and aluminium oxide and aluminium nitride, thickness are 300-3000

, and thickness from 1000 to 2000

Better.Halogen infrared ray emission lamp can be used as the irradiation intense light source.High light (or pulsed light) meaning that is equivalent to laser beam is luminous energy or itself and the mixing of the heat energy of assisting, in very short period, be generally 5 minutes during, it is applied on the semiconductor film, so that recover the degree of crystallinity of this film.

The invention is characterized in,, be used for protecting laser beam or the high light radiation active layer equivalent, to recover to be different from the film of diaphragm as gate insulating film with one deck after the crystalline layer of this active layer with it removing previous setting.This step has been improved the characteristic of resulting TFT significantly.Can improve the reason of TFT characteristic and think as follows, transfer crystalline solid to by amorphous state, often find that the mixture of many non-stoichiometry proportionings is enlarging at the interface, especially, the Si oxide of Silicon-rich exists near interface to form.And both being not enough to insulator, the mixture of these non-stoichiometry proportionings had been not enough to semi-conductive effect.Therefore very clear, the Si oxide that the non-stoichiometry proportioning occurs has hindered the acquisition superperformance, because prove conclusively, in the insulated gate element, the interface plays an important role.

If need not any diaphragm, allow laser beam or high light direct irradiation this film equivalent with it, so, will develop into a kind of irregular surface on it.The very poor element of characteristic will be made in the surface of this injustice of result.Remove the step of the protective layer that once had been provided with, be equivalent to remove the Si oxide of above-mentioned non-stoichiometry proportioning, provide the pure silicon of well-crystallized.More particularly, it is found that, remove diaphragm with the wet etching agent of hydrofluoric acid and so on and can obtain good effect.The dry etching method can cause damage to silicon fiml, and still, wet etching is owing to before the two keys of the formation of silicon atom, end at the stretched wire key of fluorine and hydrogen, so just have the surface of a stabilizer pole.

Among the present invention, by the degree of depth in equivalent high light annealing formation of laser beam or its district, according to Japanese patent application No. flat-the disclosed inventor's of 3-50793 invention, can require setting arbitrarily and control with institute.Like this, can obtain to comprise double-deck active structure, and reduce the leakage current between the drain region in source region.

According to the present invention, select laser beam for use or handle, and from 100 to 500 ℃ of heated substrate in addition are typically 300 to 400 ℃ by infrared ray (IR) photo-annealing that the IR lamp produces.In this case, the inhomogeneity film that can be improved.

Execute the peripheral circuit that example provides active array (AM) driving liquid crystal display (LCD) device of a kind of employing amorphous silicon (a-Si) TFT according to first of the present invention's application.Using an alkali-free glass, such as healthy and free from worry ^#On the substrate that 7059 glass (production of Corning company) are made, usually in 400 ℃ or lower temperature range, form a-SiTFT, obtain a-Si TFT-AMLCD:a-Si TFT thus and have the high resistance break that closes, thereby be the most suitable a kind of switch element, yet, said already that it can not make CMOS, only allowed tick-over again.Therefore, peripheral drive circuit is often made with monocrystalline IC, and the method that meets (TAB) with automatic tape welding that is connected then of face array termination and IC termination realizes.But this Setup Type will reduce pixel size can run into bigger difficulty, so installation cost will rise by the big percentage of total module cost.

Because the restriction of heating on the identical substrate of array, is difficult to make peripheral circuit with common process.Yet, but can under the temperature that is equivalent to conventional a-Si TFT formation, make TFT with high mobility for the present invention.

Use the second embodiment of the present invention, be included in material, on soda-lime glass, that is to say, forming TFT on than the also low material of cost with alkali-free glass.Under the situation, preferably to add the last layer insulator coating on glass earlier like this,, can invade TFT from glass because resemble the movable ion of sodium ion and so in order to avoid TFT directly contacts with soda-lime glass.This insulating coating can comprise as main member resembling silicon nitride, aluminium oxide or aluminium nitride.So, will be formed on the insulator coating of gained by the underlying insulation film of silica and so on, make TFT according to process of the present invention once more.And, by optimizing, cover with PTFT and make array TFT on the NTFT, can also avoid the inefficacy of this device.When movable ion invades NTFT by substrate, tend to form a raceway groove, make NTFT (ON) attitude occur out.Yet in the case, PTFT does not have raceway groove and forms.

Use the third embodiment of the present invention, comprise that direct multichannel is driving, the peripheral circuit of the LCD (LCD) that the single array of just a kind of static state drives.For example, the ferroelectric liquid crystal has store function, therefore, even when they are driven by single array, also provides the demonstration of high-contrast.The same procedure of for this reason pressing a-Si TFTAMLCD is taked TAB method and so on connection IC and is made peripheral circuit but usually.Equally, be used for by cholesterine (Cholesteric) mutually to also having made according to a conventional method by the TAB connection method to the peripheral circuit of the quiescent operation LCD that the phase transformation characteristics are arranged that is listed as (nematic) phase.Among the JP-A-61-1152 (term " JP-A " means a uncensored disclosed Japanese patent application), advised that one comprises the static drive LCD of the composition of nematic liquid crystal and ferroelectric polymer, yet this LCD also comprises the peripheral circuit that TAB connects.

Above-mentioned all LCD that enumerate are that direct multichannel drives, so they all have the high accuracy large area display that adopts low-cost substrate.If can reduce the distance between the termination, just can obtain exquisite display, but just IC installs difficulty, make expensive.So as can be seen, the present invention can provide the peripheral circuit monolithic of the low-cost substrate of a kind of usefulness, but also not perplexed by heat problem.

Use the fourth embodiment of the present invention and provide a kind of three-dimensional IC, this IC is included on the semiconducter IC of making metal interconnecting wires and forms TFT.Also have other and various application all can utilize advantage of the present invention.

Description of drawings

Fig. 1 (A)-(E) is the profile of TFT, and each step of making TFT continuously is described according to the present invention;

Fig. 2 (A)-(E) is the profile of another kind of TFT, and each step of making TFT continuously is described according to the present invention;

Fig. 3 (A)-(D) is the profile of another TFT, and each step of making TFT continuously is described according to the present invention;

Fig. 4 (A)-(C) is that graphic extension is according to LCD fundamental diagram of the present invention;

Fig. 5 is the profile of explanation according to LCD cellular construction of the present invention;

Fig. 6 (A) and (B) be to show according to TFT performance diagram of the present invention;

Fig. 7 (A)-(D) is the profile of the method for explanation TFT constructed in accordance;

Fig. 8 (A)-(E) is the profile of the another kind of method of explanation TFT constructed in accordance;

Fig. 9 (A)-(E) is the profile of another method of explanation TFT constructed in accordance;

Figure 10 (A)-(E) is the profile of another method of explanation TFT constructed in accordance;

Figure 11 is according to the partial elevation view in the circuit diagram of active array circuit of the present invention and peripheral circuit;

Figure 12 (A)-(E) is the profile that also has a kind of method of explanation TFT constructed in accordance;

Figure 13 (A)-(D) is the profile that explanation the present invention makes the also further method of TFT;

Figure 14 (A)-(D) is the profile of the other method of explanation TFT constructed in accordance;

Figure 15 (A)-(D) is the profile of the other again method of explanation TFT constructed in accordance;

Figure 16 (A)-(E) is the profile of further force method again of explanation TFT constructed in accordance; And

Figure 17 (A)-(E) is the profile that also has a kind of method of explanation TFT constructed in accordance.

Embodiment

Embodiment referring to detail description illustrates in greater detail the present invention.In any case should be known in, the present invention should not think and is limited to this.

Embodiment 1

Made the peripheral circuit that the active array (AM) that adopts a-Si TFT drives liquid crystal device (LCD) according to the present invention.As mentioned above, the conventional AMLCD based on a-SiTFT is made by the TAB interconnection approach, therefore, can not form the monolithic peripheral circuit of array.

Yet the processing of TAB method is expensive, because the cost of high interconnection will be added in the cost of IC.The total cost of IC and interconnection add up to account for whole plate cost 20% or bigger.Realize a kind of plate cheaply according to the present invention, this is owing to make monolithic array and the event of peripheral circuit on single glass substrate.

At first, with sputter under the oxygen atmosphere or decompose TEOS and by the plasma CVD deposition silica, the silicon oxide film 102 that go up to form thickness 100 to 300nm in healthy and free from worry #7059 glass substrate 101 (area is 300mm x300mm or 100mm x 100mm) is 450 to 650 ℃ of annealing down in temperature range then as the substrate oxide-film.

Then, by plasma CVD or LPCVD method deposition of amorphous silicon film 103, thickness is 30 to 150nm, and with 50 to 100nm for well, silicon oxide deposition film or silicon nitride film are as protective layer 104 again thereon, and thickness is 20 to 100nm, arrives 70nm for well with thickness 50.Operation wavelength 248nm, the KrF excimer laser pulse of pulsewidth 20nsec is by silica or silicon nitride film irradiation amorphous silicon film 103, with the degree of crystallinity of improvement silicon fiml 103.This step is shown in Fig. 1 (H).It is 250 to 400mj/cm that institute adds laser beam energy density ², and be 250 to 300mj/cm with density ²For good, so, the degree of crystallinity of research institute's deposit silicon fiml, Raman (Raman) scattering spectra shows that corresponding broad peak is positioned at 515cm approximately ^-1, in other words, this peak be different from monocrystalline silicon given should appear at 521cm ^-1The peak.When using laser irradiation, by it is implemented assistant heating, be heated to 100 to 500 ℃, can also obtain more uniform crystalline solid.The crystalline solid of gained is the hydrogen annealing under 350 ℃ 2 hours again.

Subsequently, remove protective layer 104, silicon layer 103 is exposed, and the surface that will expose is carved into the pattern of similar island shape, make NTFT district 105 and PTFT district 106.And, by sputter in oxygen atmosphere or by decomposing TEOS and the resulting film of ion CVD method deposit, also in 450 to 650 ℃ temperature range, anneal, to form gate oxidation films 107.Process then, promptly the plasma CVD process is very careful in handling the large tracts of land substrate, because during processing, substrate can produce deformation and contraction because of heating.If such deformation and contraction take place on substrate, carry out the mask alignment process in the making step later on, will encounter difficulties.On the other hand, in sputter procedure, can remain on 150 ℃ of temperature or lower to substrate.And, be preferably in the hydrogen and anneal under about 450 ℃, so that stretched wire key of film inboard and so on reduces, thereby prevent that gate oxidation films is subjected to the influence of fixed charge.

After this, the deposited by electron beam evaporation sedimentation, again deposition thickness be 200nm to 5nm aluminium film, be carved into pattern then, obtain the gate contact zone 108 and 109 that illustrates as Fig. 1 (B).In the time of with form gate contact zone 108 and 109, also form the grid contact 110 of the TFT (anticlinal row type) of active array circuit.

Fig. 1 (C) illustrates the mode that forms anodic oxide coating 111 to 113 around gate contact zone.This process comprises electric current is added on the gate contact zone that is dipped into the substrate in the electrolyte.In carrying out this step, the TFT (this TFT is positioned at the left side of figure) that is preferably in peripheral circuit region goes up the anode oxide film of making and will approach as much as possible, to increase mobility, make thick anode oxide film with corresponding partly then the making of active array part TFT (being positioned at figure right side anticlinal row TFT), thereby can prevent grid leak.Formed in the present embodiment anodic oxidation film thickness arrives the 250nm scope 200.

Impurity is mixed the island shape silicon fiml of each TFT, this be with the grid contact portion (be gate contact zone and around anode oxide film) for sheltering, carry out ion doping with Alignment Method.Carry out in this technology, earlier with phosphine (PH ₃) as impurity gas, phosphorus is all injected on whole surface, then, only covers island district 105 with photoresist, uses diborane (B again ₂H ₆) for impurity gas injects boron, make boron only mix island district 106.The phosphorus that this step is mixed and the dosage of boron are respectively 2 x 10 ¹⁵To 8 x 10 ¹⁵/ cm ²With 4 x 10 ¹⁵To 10 x10 ¹⁵/ cm ², like this, the dosage of boron will be higher than the dosage of phosphorus.

Then, the structure of last gained is shown in Fig. 1 (D), and stand the wavelength that the KrF excimer laser launched is 248mm, and the work pulsewidth is that the laser of the light of 20nsec comes irradiation, makes because of the part of damaging of accepting to mix to recover its degree of crystallinity.Add laser beam energy density be 200 to 400mj/cm ², be preferably 250 to 300mj/cm ²By carrying out the assistant heating method, be warmed to 100 to 500 ℃ scope, can also obtain uniform crystal.

Obtained N-type district 114 and 115 like this, and P-type district 116 and 117.The layer resistivity in these districts all 200 to 800 Ω/ Scope in.

Then, in whole surface, the thick silicon oxide film of sputtering sedimentation one deck 300nm is as intermediate insulating layer 108.This silicon oxide film also can be replaced with the silicon nitride film of plasma CVD deposit.The film of Huo Deing only plays intermediary's insulating barrier in peripheral circuit like this, still, when this layer is applied to the active array part, must take care in the mill, because this layer also will be as the gate insulation layer of TFT later on.

Then, deposition thickness 20 arrives the amorphous silicon layer 119 of 50nm on the gate contact zone 110 of active array part, and is used as the microcrystal silicon layer of source/leakage of α-SiTFT, then uses the plasma CVD method deposit, and forming thickness is 50 to 100nm.Resulting microcrystalline sillicon film is carved into pattern, thus acquisition source/ leakage 120 and 121.

Then, in the TFT source/leakage of peripheral circuit, leave contact hole, make aluminum interconnecting 122,123 and 124.By this situation, can see that on the left side, NTFT and PTFT have formed an inverter circuit.And, by the optical transparency electric conducting material, on the TFT of active array part, formed pixel capacitors 125 as ITO.At last, in hydrogen,, the dangling bonds in the silicon fiml is reduced, the structure of gained to obtain to have the integrated monolithic peripheral circuit of source array circuit 350 ℃ of annealing 2 hours down.In the present embodiment,, enter the raceway groove position to prevent incident light, because the conductivity of α-Si easily changes with radiant light with the α-SiTFT of anti-diplarthrous TFT as active array.Needn't say again,, shield TFT and be not subjected to exterior light irradiation, can be used for plane TFT equally if will take the effective precautionary measures.

The illustrative example of the TFT characteristic that is disposed in the peripheral circuit according to the present embodiment manufacturing is illustrated among Fig. 6.Under vacuum, with the 50nm thick silicon fiml of KrF laser beam irradiation, on this film, form the thick diaphragm of 20nm, and make the silicon fiml crystallization by the LPCVD deposit, obtain TFT thus.This KrF laser is at energy density 250mj/cm ²Following work is implemented 10 irradiations to silicon fiml.So, remove protective layer after, thereon again by the thick 120nm silica of sputtering deposit, and obtain gate medium.After forming gate contact zone, form the anode oxide film of thick 206nm, the mask that injects as follow-up ion with anodic oxidation.By phosphonium ion that accelerates to the 65Kev energy and the boron ion that accelerates to 80Kev, bombard this structure, inject and carry out ion, make doped region with self-aligned manner, after this, in air, be 300mj/cm with the energy density ²Pulse KrF laser beam irradiation 10 times, activate.

Fig. 6 (A) and Fig. 6 (B) illustrate the characteristic of NTFT and PTFT respectively.The raceway groove of this TFT is grown 3.5 μ m and wide 15 μ m, and being seen mobility is 600cm in NTFT ²/ vs, and be 30cm in PTFT ²/ vs.And, show the S value of the steepness that TFT opens/breaks NTFT is drawn 0.42V/ unit, and PTFT to be a 0.53V/ unit.Finding NTFT threshold voltage is 3.9V, and being seen PTFT threshold voltage then is-5.4V.To 1V or-open/break ratio under the 1V drain voltage, be 8.7 unit of measurement to NTFT, and PTFT is 6.9 units.

Embodiment 2

Present embodiment provides a kind of active array that forms on the soda-lime glass substrate.Because soda-lime glass is rich in sodium, thus will be at thick 1.1mm, area 300 x 400mm ²The whole surface of soda-lime glass substrate 201 on plasma CVD method deposit thick 5 to 50nm, preferably thick 5 to 20nm nitrogenize coating 202.Top silicon nitride is used to prevent that sodium from diffusing into thin-film transistor from the soda-lime glass substrate.By with silicon nitride or pellumina covering substrate, thus this technology that the barrier layer is set on substrate be disclosed in Japanese patent application flat-3-238710 peace-3-238714, this is applied for by the inventor.In addition, cover layer 202 also can be an aluminium nitride film.

Like this, after forming as the silicon oxide film of substrate oxide-film 203, using plasma CVD or LPCVD technology deposit silicon fiml 204, its thickness are 30 to 150nm, preferably are 30 to 50nm, and thereon silicon oxide deposition film 205 as protective layer.Shown in Fig. 2 (A), make the structure of formation accept the laser radiation of KrF excimer, improve the degree of crystallinity of silicon fiml 204 with this.The energy density of the laser beam that is applied is 150 to 200mj/cm ², promptly be lower than the value of the laser beam that embodiment 1 adopted slightly.And only apply 10 emissions.Therefore, find that the degree of crystallinity of silicon fiml of deposit like this is than the more approaching sub-amorphous state of embodiment 1.In fact, the silicon fiml hole mobility that produces in this example, specifically, this is worth 3 to 10cm ²The scope of/vs is lower than the value of the silicon fiml of embodiment 1.

Then, remove protective layer silicon layer is exposed, island graph area 206 is made on the surface of exposure, thereby set up grid oxidation film 207 thereon by sputter, thickness is 50 to 300nm, is preferably 70 to 150nm.Then, press the mode of embodiment 1, deposit aluminium film also makes its Butut, obtain gate contact 208 thus, and gate contact is centered on by anodic oxide 209.The structure that forms is shown in Fig. 2 (B).

Mix up by ion with self-aligned manner, boron is imported silicon layer as p type impurity, form the source/leakage of thin-film transistor thus.Then, shown in Fig. 2 (C), adopt KrF excimer laser that the structure that forms is carried out laser beam irradiation, so that the degree of crystallinity of the part that suffers damage because of importing impurity is recovered.The energy density of the laser beam that is applied up to 250 to 300mj/cm ²Therefore, layer resistivity 400 to 800 Ω/ , this value is better than the value of embodiment 1, and is applicable to the source/leakage of thin-film transistor.

So the thin-film transistor that obtains comprises an active layer with less mobility.But the best active matrix that also is to use, more particularly, the thin-film transistor that this example obtains has the high resistance of opening, however it closes resistance break still sufficiently greater than opening resistance.Therefore, required additional capacitor no longer needs usually.Particularly, ion such as sodium are promptly moved in the source of the leakage current in N-channel MOS, can not throw into question in the P channel device that this example is quoted.

Can implement last being limited under 350 ℃ the low temperature according to the treatment process in the present embodiment.But when the formation of silicon nitride film or silicon oxide film, can reach the highest allowable temperature.Surpass the upper limit if temperature rises, soda-lime glass will soften.In this K cryogenic treatment, the defective in the grid oxidation film can cause problem sometimes.In the situation of embodiment 1, in the temperature that is higher than 450 ℃ gate oxidation is annealed, because substrate has quite high thermal endurance, so can under so high temperature, carry out thermal annealing.But present embodiment adopts the soda-lime glass substrate, so can not implement this thermal annealing.Therefore, a large amount of fixed charges mainly are that positive charge will reside in the grid oxidation film.This shows that formed structure can not be used for N channel-type MOS, because the existence of these fixed charges has produced excessive leakage current.Yet in the P channel MOS, although fixed charge is certain to influence threshold voltage, leakage current can be suppressed lessly, thereby the fundamental characteristics that is used for active matrix work can be realized.And, with the high-energy-density laser beam source/leakage is annealed, thereby produce little sheet resistance.This causes suppressing signal delay.

Then, form interlayer insulation body 212 with polyimides.After this step, use ITO to form pixel capacitors 213.The source/drain region that contact hole is used at thin-film transistor TFT is set then forms aluminium contact 214 and 215.So one of contact that forms 215 is connected with ITO.At last, under 300 ℃, the structure of last formation is carried out 2 hours annealing, thereby finish the hydrogenation of silicon at hydrogen.

Form four active matrixs on the single substrate that is in the end obtained, total is cut into four, obtains four active matrix utmost points thus.The active matrix of Huo Deing does not have peripheral circuit like this, and has only need by TAB and so on technology and after driver IC is connected, and just can make its driving.Yet, owing to substituted normally used alkali-free glass substrate among α-Si thin-film transistor AMLCD with soda-lime glass substrate cheaply, thereby total cost is better than the cost of traditional plate.Particularly, the plate according to present embodiment is particularly suitable for large-area trickle demonstration.So the Active Matrix LCD At that obtains is in Figure 11.Active matrix 925 is connected with peripheral circuit 951, and peripheral circuit comprises driver thin film transistor and offset resistance.The pixel 935 of active matrix comprises thin-film transistor 956, liquid crystal layer 954 and auxiliary capacitor 955.

For example, a α-Si thin-film transistor has 0.5 to 1.0cm ²Mobility in the/vs scope, it can not be used for surpassing the extensive matrix of 1000 row.On the contrary, the mobility that has according to the thin-film transistor of present embodiment is 3 to 10 times of traditional thin-film transistor, and it can be used for this large-scale matrix and not have any problem.In addition, it can show in response to analog layering satisfactorily.

And, because gate line and data wire be each made of aluminum, even thereby surpass on 20 inches the large display screen at diagonal, also can obviously reduce the delay and the decay of signal.

Embodiment 3

Present embodiment provides a kind of high-contrast LCD LCD, has these two advantages of memory function of diode characteristic and ferroelectric polymers, thus adopt the peripheral circuit monolithic be integrated in single on-chip technology reduction manufacturing cost.The similar of this LCD in for example Japanese patent application clear-the disclosed structure of 61-1152.

Such LCD allows semi-static work.Therefore, although the TN liquid crystal is the mode work that drives with direct multichannel, still can obtain Very High Contrast's demonstration.In addition, opposite with the mim type non-linear element, in manufacturing process, do not have problems.Its operation principle as shown in Figure 4.

Usually, ferroelectric E (electric field)-(dielectric (flux) density) characteristic is the hysteresis curve, shown in Fig. 4 (A).Promptly form constant polarization intensity under certain external electric field in the ferroelectric material, after the electric field that applies surpassed a determined value, polarization intensity was reversed.If consider a circuit, this just means charge transfer, thereby wherein just produces electric current.For example, can consider a series circuit, comprise that establishing ferroelectric electric capacity (FE) and one between electrode for one establishes for example electric capacity of liquid crystal (LC, capacitance is C) of a kind of material between electrode.In actual applications, a common quite high resistance R in parallel with ferroelectric condenser.Therefore, the structure of a side circuit formation is shown in Fig. 4 (C).Yet, should be noted that PE not only plays the function of a simple capacitor, but also be a nonlinear resistor.In the circuit that forms, change as Fig. 4 (B) shown in based on the electric current of the alternating current that imposes on circuit, thereby present nonlinear characteristic formation hysteresis curve.

When facing to one of electrode on apply-V.Or O voltage, and on another electrode, apply O or V.During voltage, the voltage of unit will be ± 2V.With one of among the O.If voltage becomes ± 2V.Or-2V., shown in Fig. 4 (B), sharply descend in its change procedure of the resistance of FE, this means that the electric charge of q.s imposes on LC.If change in voltage is+V.、-V。With in the O value any one, the resistance of FE can significantly not descend this moment.Therefore, should consider from the leakage current of parallel resistance R this moment.Because discharge appears in leakage current, LC.Can find out ± 2V thus.Stage corresponding to the choice phase, corresponding sub non-choice phase in other in stage.

Referring to Fig. 4 (B), the straight line representative of drawing by origin of coordinate and by dotted line is because the leakage current that R occurs, and when using this device as LCD LCD, concerns particular importance between R and the C.Although there is not detailed discussion here, if timeconstant=RC much smaller than frame time, then only forms low contrast, because this means that the contribution of FE is very little.On the other hand, if big more a lot of than frame time, the result is that image is full of the interference demonstration afterwards.Therefore, should be set at as much as possible near frame time.

Fig. 5 schematically represents a unit.This unit is to constitute like this, and liquid crystal material 512 is clipped between two substrates 501 and 502, and is identical with common LCD.In order to make element thickness even, spacer 511 is inserted between the substrate.Spendable liquid crystal material comprises twisted nematic liquid crystals, super-twist nematic liquid crystal, adopt nematic crystal, the ferroelectric liquid crystals of birefringent non-distortion, the diffusion-type liquid crystal (PDLC) that comprises polymer, wherein liquid crystal such as nematic crystal or cholesterine (Cholesteric) liquid crystal is by disperse.

The same with the simple matrix liquid crystal of common employing, the transparent band electrode 505 and 506 that setting is made by ITO or other similar material, make their mutual square crossings, with common simple matrix structure difference be, the electrically conducting transparent cover layer of ITO or other material is an island, this island layer forms son and spreads all over electrode 506, is provided with ferroelectric polymers 507 between the two.Form oriented film 509 and 510 in order to cover these electrodes.This structure has detailed description in Japanese patent application 1152/1986.

Connect IC by traditional approach by TAB, the LCD of formation like this is driven.This configuration has some restriction.At first, in the LCD of this device, the magnitude of voltage that dummy adds to liquid crystal is 1 or 0, and this voltage is continuously applied with this and reaches high-contrast during a frame whole, and this is a feature of this device.Therefore, during with various grey standard displayed image, be difficult to finish analog gray scale and show, to be that Thin Film Transistor-LCD is common do for this.And, all inapplicable for pulse modulation method that is adopted in the stn liquid crystal display and frame modulator approach.As a result, two dimensional gray is depended in liquid crystal display, and this has greatly increased the quantity of pixel.

The problems referred to above are not have in essence difficulty for this LCD.In other words, because this LCD is simple in structure, can quite easily realize mass matrix.Yet, in fact, when the terminal that connects reaches the density of 20 lines per millimeters, be not suitable for using the TAB device.In addition, be difficult to adopt COG that chip is covered method on glass and make LCD.Therefore, must be integrally formed in peripheral circuit on the same substrate.

For example, in order to reach the two dimensional gray of 64 grey standards, each pixel needs 6 subpixel.Thereby the quantity of required row is the two or three times of the line number of common matrix structure.If this device is used for the high definition screen according to the XGA standard, the quantity of row will reach 1500 to 3000.Even at diagonal is the situation of 15 inches large scale screen, need the density of 10 to 15 lines per millimeters.When screen narrows down, need the image compression of higher density.Especially, when LCD that adopts native system and high-transmission rate liquid crystal PDLC bundle formation projection screen, the diagonal of substrate is less than 5 inches.

At this moment, except the high density image compression, also need high speed integrated circuit work.In this situation, the circuit on the insulating substrate comparatively is difficult for loss than the circuit on the single crystal semiconductor substrate, and can be with high speed operation.Yet, if mobility resembles the embodiment 2 less than 10cm ²/ vs then adopts the sort of configuration to have problems.Therefore, need mobility greater than 30cm ²/ vs is more preferably greater than 50cm ²/ vs.

For this reason, the high light that wish to adopt laser annealing or be similar to laser is done K cryogenic treatment.The manufacturing process of peripheral circuit shown in Figure 3 below is described.Make substrate 301 with healthy and free from worry (Corning) 7059 glass or other similar alkali-free glass substrate.This sizes of substrate is 300mmx400mm.On substrate, the oxide-film of being made by silica 302 is as basic unit.In addition, form silicon layer 303 and protective layer 304, shown in Fig. 3 (A), under the condition identical, shine laminated with laser emission with embodiment 1.

Then, the silicon layer photoetching is patterned in island, forms N type thin-film transistor (NTFT) district 305 and P type thin-film transistor (PTFT) district 306, and make grid oxidation film 307 by silica with this.Shown in Fig. 3 (B), form aluminum gate electrode 308 and 309, because aluminium must stand the laser radiation of back, adopt electron beam evaporation to form aluminum gate electrode, have high reflectance on it so that make, the about 1 μ m of aluminium grain size that forms by sputter, and the tectal surface of aluminium is very coarse.Therefore, when the aluminium cover layer was shone by laser emission, cover layer was by badly damaged.The aluminium film surface that is formed by electron beam evaporation is so level and smooth, so that can't see the existence of crystal grain with light microscope.Disclose crystallite dimension less than 200nm by electron microscope observation.In other words, the product particle size must be less than the wavelength of employed laser emission.

Afterwards, N type dopant or phosphonium ion are injected 310 districts and 311 districts, P type doping agent or boron iontophoresis 312 and 313 districts.Shown in Fig. 3 (C), implement laser annealing and handle.Under the condition identical, carry out laser radiation with embodiment 1 and example 2.In this processing procedure, aluminum gate electrode is not damaged basically.

At last, shown in Fig. 3 (D), make interlayer insulation body 314 and form contact hole therein by silica.Form aluminium interconnecting line 315-317, be used for the interconnection film transistor.Finish peripheral circuit thus.Form banded ITO film (not shown) and pixel capacitors then.The substrate quartering, each is of a size of 150mm x 200mm.In such a way, obtain four substrates.By Japanese patent application 1152/1986 described method cited above, deposit ferroelectric polymers or analog on two substrates, then two substrates by bonding together as shown in Figure 5, thereby constitute a LCD.

Embodiment 4

Present embodiment as shown in Figure 7.This is to adopt novel laser crystallization silicon thin film transistor in the peripheral circuit that tft liquid crystal shows.Different with embodiment 1, the TFTS (thin-film transistor) in the active matrix circuit district is made of top grid amorphous silicon, and promptly grid is positioned at a relative side of substrate.In this example, can adopt identical manufacturing process to prepare the active layer of two kinds of thin-film transistors, but that condition is wanted slightly is strict, because needs laser crystallization characteristic and amorphous silicon characteristic preferably preferably.Active matrix circuit and peripheral circuit are arranged on the insulating substrate.

At first, by sputter the oxide-film 702 that constitutes basic unit is deposited on the substrate of healthy and free from worry (Corning) 7059 glass, thickness reaches 20 to 200nm, by plasma CVD single monosilane or disilane be essentially amorphous silicon film and be deposited on the oxide-film 702, thickness is 50 to 150nm.At this moment, be essentially amorphous silicon film and need be directly used in amorphous silicon film transistor, and stand laser radiation.We can find, if substantially for substrate temperature during the preparation of amorphous silicon film is set in 300～400 ℃, then can improve the characteristic of this amorphous silicon film, forming thickness once more by sputter on this amorphous silicon film is 10 to 50nm silica diaphragm 705.Then, 706 cover the active matrix circuit district with photoresist, and only peripheral circuit is carried out laser radiation, improve the degree of crystallinity that is essentially amorphous silicon film of peripheral circuit with this.

Under this condition, shown in Fig. 7 (A), finish laser radiation like that.Employed laser species is identical with embodiment 1 with condition.Yet at this moment, owing to following reason, the energy density of laser is preferably 200 to 250mj/cm ²Contain excessive hydrogen in the amorphous silicon membrane that is formed by plasma CVD, if with light laser it is shone, hydrogen can become gaseous state and expand, thereby damages film.As the above-mentioned institute silicon fiml of saying by crystallization and form crystallization region 704.On the other hand, those parts that covered by photoresist are without laser radiation, thereby remain amorphous state.

Then, silicon fiml is carried out island shape Butut, make its island district that is formed for peripheral circuit 707 and the island district 708 that is used for the active matrix district, shown in Fig. 7 (B).The sputter silica forms phase utmost point dielectric film 709 in these island districts.Mode by embodiment 1 forms the gate metal electrode 710,711 and 712 that its surface has anode oxide film.

Then, shown in Fig. 7 (C), use gate electrode 710 and 712 as mask, N type impurity Lead-In Area 713 and 715.With gate electrode 711 as mask p type impurity injection region 714.Under the condition identical with embodiment 1, as mask, these districts are carried out laser radiation with gate electrode, make district's crystallization of injection.Obtain the silicon of high-crystallinity there.District 716 and district be 717 in the crystallization already of the stage of Fig. 7 (A), but distinguish 718 in the not crystallization as yet of this step.In other words, in the thin-film transistor (thin-film transistor in active matrix district) on Fig. 7 right side, source and leak crystallization, but active area is still amorphous silicon semiconductor in fact.The active area 76 and 717 that centers on thin-film transistor in the peripheral circuit of active matrix circuit comprises the crystallization semiconductor.

At last, be that 400 to 1000nm silicon oxide film is as interlayer insulation body 719 by tetraethyl orthosilicate (TEOS) plasma CVD deposition thickness.Then, forming thickness in the active matrix district is 100 to 300nm ITO film 720.This ITO film is carried out Butut form pixel capacitors.In the interlayer insulation body, form contact hole.On the interlayer insulation body, form metal wiring layer 721-724.Make the thin film transistor active matrix LCD thus.

In this LCD, the degree of crystallinity of the active area of thin-film transistor low than the active area of thin-film transistor in the peripheral circuit in the active matrix circuit.The active area of thin-film transistor comes down to amorphous silicon film in the active matrix circuit, and its resistivity is 10 when dark ⁹Ω cm or bigger.

In the present embodiment, by the mode identical with embodiment 1, the thin-film transistor that constitutes pixel is made by amorphous silicon film transistor, and it presents high resistivity under turn-off criterion.Yet thin-film transistor that embodiment 1 adopts is reverse interleaved formula.In the present embodiment, thin-film transistor is the top gate type.In embodiment 1, except the preparation technology of gate electrode, the preparation process of the thin-film transistor of peripheral circuit is different from the preparation process of the thin-film transistor of active matrix circuit.Therefore, increased step number.In the present embodiment, the thin-film transistor of the thin-film transistor of peripheral circuit and active matrix circuit is made simultaneously.Thereby the quantity of the few manufacturing step of energy alkali.

The silicon fiml that is applicable to amorphous silicon film transistor also needs to contain a large amount of hydrogen.Yet, in order to make the thin-film transistor crystallization with laser radiation.Must reduce hydrogen content as much as possible.Because these two kinds of demands are conflicting, must form the silicon fiml that can satisfy two kinds of conditions.For example, when using plasma CVD, if with high-energy plasma body such as electrochemical reaction (ECR) plasma or microwave etc. from form silicon fiml in body, then contain a large amount of haptophores in the film.This purpose to present embodiment is perfect.Yet there is the low slightly problem of resistivity under the turn-off criterion in it.

Embodiment 5

Present embodiment as shown in Figure 8.At embodiment 1-4, thin film transistor region is separated, thereby makes its electrically insulated from one another.In the present embodiment, on whole surface, form silicon fiml and crystallization selectively.And, use thick insulating film to make the thin-film transistor mutually insulated.

At first, the silicon oxide film 802 of deposit formation basic unit on insulating substrate 801.On silicon oxide film 802, form thick 50 to 150nm be essentially amorphous silicon film or have silicon fiml with the equal low-crystallinity of degree of crystallinity of this amorphous silicon film.In the present embodiment, being essentially amorphous silicon film must stand enough laser radiations and present high resistivity.Therefore, preparation is essentially amorphous silicon film under the condition identical with embodiment 4.Then, by plasma CVD, on the whole surface of amorphous silicon film, form thick 10, best 10 to 50nm silicon oxide film (dielectric film) to 500nm.Silicon oxide film (dielectric film) is carried out selectively etching, thereby the zone of silicon oxide film (dielectric film) or the zone that silicon oxide film (dielectric film) is thinned are removed in acquisition at this place.Form thick silicon oxide film district 805 and thin silicon oxide film district 806 thus.At this moment, if adopt isotropic etching technique, then form the step of level and smooth inclination.Shown in Fig. 8 (H).Therefore, can avoid the fracture of the metal wiring layer that causes because of precipitous step.

With this understanding, do slight doping with boron ion pair one is laminated, and make the silicon fiml crystallization with laser radiation.The result shown in Fig. 8 (A), amorphous silicon layer by crystallization silicon oxide film remove or the described zone of attenuation under the degree of crystallinity of the silicon fiml part 804 that is provided be enhanced.Other district 803 remains amorphous state.Because boron mixes, district 804 presents the weak P type of intrinsic-OR in fact.

Can implement this step by method shown in Fig. 8 (E): specifically, after forming silicon oxide film, form a cover layer on silicon oxide film, basic thickness is 20 to 500nm, and is made by the material of the light of reflector laser.This cover layer is carried out the photoetching Butut.Utilize this cover layer 819 as mask, silicon oxide film is carried out isotropic etching.Thus, form thick district 817 and thin district 818 at silicon oxide layer.Shine repeatedly sending layer with laser emission, stay mask 819 simultaneously, amorphous silicon film is carried out selectively crystallization.In such a way, form crystallization region 816 and amorphous silicon region 815.

Shown in Fig. 8 (B), form grid oxidation film 807 or silica then, be used for producing gate metal electrode 808 and which is provided with anodic oxide coating.Owing to adopt wet etching that metal gates is carried out etching, so the side surface of grid is the slope.This shape can effectively prevent the fracture of conducting wiring layer in the crosspoint.

Shown in Fig. 8 (C), make mask with gate electrode and thick silicon oxide film district 805, with ion doping at least a impurity is selectively injected silicon fiml, thereby form N type district 809 and p type island region 810.With laser emission these districts are shone with this and to be made its activation.Afterwards, shown in Fig. 8 (D), deposit interlayer insulation 811, and form contact hole therein.Form metal wiring layer 812-814, thereby finish circuit.In the present embodiment, a large amount of light tight amorphous silicons are stayed on the substrate, and therefore this structure can not be used as the matrix district, source of liquid crystal display.Yet it can be used as the drive circuit of peripheral circuit region or image sensor.The active layer of quite thick (100nm) if desired in the present embodiment, the step of each element that is used to insulate is just few.Therefore, can reduce the possibility of conducting wiring fault rupture widely.In high density integrated circuit, this advantage is particularly remarkable.

Embodiment 6

Present embodiment is as shown in Figure 9, and is similar to Example 5, form on whole surface silicon layer and selectively crystallization so that each element isolate mutually.Owing to do not adopt the uneven oxide-film among the embodiment 5, thereby can more effectively avoid the fracture of wiring layer.

At first, on insulating substrate 901 silicon oxide deposition film 902 as basic unit.On silicon oxide film 902, form thick 50 to 150nm the film that is essentially amorphous silicon, perhaps deposit has the silicon fiml with the equal low-crystallinity of degree of crystallinity of this amorphous silicon film.In the present embodiment, the film that is essentially amorphous silicon equally also must stand enough laser radiations and present high resistivity.Therefore, preparation is essentially the film of amorphous silicon under the condition identical with embodiment 4.Then, the silica diaphragm 905 of formation thick 20 to 100nm on this amorphous silicon film.Can stay this silicon oxide film 905 and constitute subsequently the gate insulating film of thin-film transistor.As previously mentioned, should notice that these thin-film transistors have low mobility.On silicon oxide film, form thick 20 to 500nm cover layer then, this cover layer is by the material of reflector laser such as aluminium, titanium, and chromium etc. are made, and is perhaps made by the material of transmission laser not.This cover layer is carried out the photoetching Butut.Shown in Fig. 9 (A), utilize this cover layer 906 as mask, use the laser radiation amorphous silicon film, the crystallization that amorphous silicon layer is selected.Thus, form crystallization region (crystalline semiconductor area) 904 and amorphous silicon semiconductor district 903.

Then, shown in Fig. 9 (B), on the new gate insulating film that forms on the crystalline semiconductor area 904, form gate metal electrode 907 and 908, have anode oxide film on the surface of this gate electrode.Because adopt wet etching that metal gates is carried out etching, sides of gate electrodes becomes the slope.This shape can be avoided the fracture of wiring layer in the crosspoint effectively.In addition, apply photoresist 909 and carry out Butut, only expose the N channel thin-film transistor.

Utilize photoresist and gate electrode as mask, N type impurity is injected silicon fiml.Under this condition, shine laminated with laser emission, activate these injection regions 912 with this.At this moment, amorphous silicon will be by crystallization, except not being the injection region but also keeping the photoresist district.Can not adopt quite thick oxide-film to isolate each element in the present embodiment, will undesirably produce and leak at each interelement.

Equally, corresponding with the P channel thin-film transistor, apply photoresist to 910.When only exposing the P channel thin-film transistor, inject p type impurity and form P type doped region 913 with this.Then, shown in Fig. 9 (C), shine laminated, stay photoresist simultaneously, activate doped P-type district 913 already with this with laser emission.In the step that has so far illustrated, laser rays is not radiated at the district 914 between N type doped region 912 and P type doped region 913.Therefore, mesozone 914 remains on the amorphous silicon state that is essentially.Therefore, if on it is the superposition insulating barrier 905 of gate insulating film, form wiring layer, and if this wiring layer form inversion layer, then leakage current is minimum, because the field mobility of amorphous silicon is very little and resistivity is very high.In fact, can not have problems.

Subsequently, shown in Fig. 9 (D), illuvium insulator 915, and in insulator, form contact hole.Form wiring layer 916-918, thereby finish circuit.In the present embodiment, the same with embodiment 5, leave a large amount of opaque amorphous silicons on the substrate, therefore this configuration can not be used as for example active matrix district of LCD, but can be used as peripheral circuit region or be used as the circuit that drives image sensor.In the present embodiment, different with embodiment 5, there is step hardly between each gate electrode.Therefore, the possible performance of wiring layer fracture reduces significantly.This advantage is particularly remarkable for the high density integrated circuit source.

Fig. 9 (E) has represented another profile of the thin-film transistor circuit of present embodiment preparation.This is the profile that passes through the N channel thin-film transistor along the Section line A-B of Fig. 9 (D).Figure as seen thus: the doped region 912,913 of crystallization is positioned at same plane with middle element isolation zone (semiconductor that separates) 914, and therefore, gate electrode 917 is smooth.Wiring layer 917 ' with doped region 913 ' contacts with gate electrode 907 only has step in the position of contact hole and the position of interlayer insulation.There is not the step of the such heavy insulation that is used for element separation of embodiment 5 in the step that neither has the such island shape semiconductor district of embodiment 1 yet.This is an advantage for make high density integrated circuit with high production rate.In the device of Fig. 9 (D), each transistor is separated from each other by the separating semiconductor 914 that is arranged between the crystalline semiconductor area 904.

Embodiment 7

Below provide an example that on the soda-lime glass substrate, forms active matrix circuit.Thick 1.1mm, area are that the soda-lime glass substrate of 300mm x 400mm is used as substrate 201.SiO ₂Film 216 is formed on the substrate 201, shown in Figure 10 (A).On the whole surface of substrate, form AlN then, SiN or Al ₂O ₃Film 202, shown in Figure 10 (A).Afterwards, implement each step by the mode identical, thereby finish active matrix circuit with embodiment 2.That is, after forming oxide-film 203 or silicon oxide film and constituting basic unit, forming silicon fiml 204 by LPCVD or plasma CVD, its thickness is 30 to 150nm, preferably 30 to 50mm, subsequently, forms silica protective layer 205.

Shown in Figure 10 (A), use KrF laser emission irradiation laminated, improve the degree of crystallinity of silicon fiml 204.At this moment, the energy density of laser emission is set in 150 to 200mj/cm ², lower slightly than the energy density of embodiment 1.The emitting times of laser emission is 10.The degree of crystallinity of the silicon fiml that forms more approaches noncrystalline attitude than embodiment 1.In fact, under this condition, the field mobility in the hole of positively charged is 3 to 10cm in the silicon fiml that is obtained ²/ vs, this is lower than implements the 1 field mobility that is obtained.Then, remove diaphragm, the silicon fiml Butut is become island-shaped area 206.Form grid oxidation film 207 by sputter, its thickness is 50 to 300nm, and preferably 70 to 150nm.Mode by embodiment 1 forms grid aluminium electrode 208.These gate electrodes 208 are covered by anodic oxidation 209, shown in Figure 10 (B).

Adopt self-aligned technology, the boron ion is injected silicon layer as P type dopant ion, form each thin-film transistor source/ leakage 210 and 211 with this.Shown in Figure 10 (C), use the KrF laser radiation laminated, improve the silicon fiml degree of crystallinity of the deterioration that causes because of ion doping.At this moment, the energy density of laser emission is set at than higher value 250 to 300mj/cm ², therefore, these sheet resistances 400 of source/leakage that thin-film transistor is arranged are to 800/cm ², the pure resistance of this and embodiment 1 is similar.

Although the mobility of active layer is less, when it was used for the active matrix thin film transistor, this little mobility still had advantage, specifically, opens the resistivity height, and it is higher to turn-off resistivity.This just makes to need not to resemble and auxiliary capacitor is set the prior art.Particularly, movable ion such as sodium ion cause the leakage current from N-channel MOS.In this example, there is not this problem, because be the P channel-type.

In this example, in the preparation of silicon nitride film or silicon oxide film, maximum processing temperature applicatory is 350 ℃.Soda-lime glass can take place softening under higher temperature.In the technology that this low temperature of needs is handled, the defective in the grid oxidation film can throw into question.In embodiment 1, the thermal endurance of substrate is fairly good, so grid oxidation film can be annealed under up to 450 ℃ temperature.Under the situation of soda-lime glass substrate, this can not reach.This causes a large amount of fixed charges to be left on grid oxidation film.In this situation, fixed charge mainly is a positive charge.Therefore, downward in the influence of fixed charge, N-channel MOS has produced a large amount of leakages in the source with between leaking, so N-channel MOS can not practical application.Yet in the P channel MOS, fixed charge can influence threshold voltage, but has kept for the work of the active matrix circuit source low leakage characteristics that is absolutely necessary.Owing to source/leakage is annealed,, and can suppress the delay of signal so sheet resistance is lower with high energy laser beam.

Afterwards, prepare interlayer insulation 212 with polyimides.Form pixel capacitors 213 with ITO, and form contact hole.On the source/drain region of thin-film transistor, form aluminium electrode 214 and 215.An electrode 215 is connected with the ITO electrode.At last, in nitrogen atmosphere, under 300 ℃,, finish the hydrogenation of silicon thus to laminated annealing 2 hours.

On a substrate that is preparing by this method, form four active matrix circuits.This substrate is divided into four active matrix boards.In this example, active matrix circuit does not have peripheral circuit.Therefore, drive integrated circult must be connected with peripheral circuit by TAB etc.Because the soda-lime glass substrate is more cheap than the alkali-free glass substrate that existing non-crystalline silicon tft AMLCD is adopted, so the substrate in this example is very favorable.Particularly, the plate for preparing in this example is suitable for the plate of large scale high definition.The active matrix that is obtained is shown schematically in Figure 11, and wherein active matrix is represented with 952.Peripheral circuit 951 has driver thin film transistor and shift register.A pixel of active matrix is by reference number 953 expressions.The thin-film transistor 956 that has also shown active matrix, liquid crystal layer 954 and auxiliary capacitor 955.

In existing amorphous silicon film transistor, the order of magnitude of mobility is 0.5 to 1.0cm ²/ vs.Thereby this thin-film transistor can not be used to have the large-size matrix greater than 1000 row.In this example, mobility is 3 to 10 times of mobility of amorphous silicon, so do not have problems.In addition, the thin-film transistor in this example is enough to show in response to analog gray scale.And gate line and data wire are made of aluminum.Surpass in 20 cun the large scale screen at diagonal, can reduce the delay and the decay of signal significantly.

Embodiment 8

The transistorized preparation case representation of membrane according to the invention is in Figure 12.At first, prepare the substrate 1101 of healthy and free from worry (Corning) 7059 glass, be of a size of 300mmx 300mm or 100mm x 1000mm.By reactive sputtering deposition techniques thick 10000 to 2000

Aluminium nitride film 1102.Use aluminium as target, carry out sputtering technology in nitrogen and argon gas atmosphere, wherein the ratio of nitrogen is more than 20%,, obtain the cover layer that it has good thermal conductivity.Wherein the pressure of sputter is 1 x 10 ^-4To 1 x 10 ^-2Torr can obtain favourable result like this.Deposition rate is 20 to 200

/ min.Substrate temperature can rise to 100-500 ℃ when deposit.

Two sides at substrate all forms aluminium nitride film 1102, in order to restriction extraneous element such as sodium, this may be contain in the substrate or load after be attached to the surface, can avoid the deterioration of tft characteristics thus.Aluminium nitride film 1102 also plays the effect that strengthens substrate surface, thereby avoids the surface by scratch.Particularly, when thin-film transistor is used for active matrix liquid crystal display, there is not the surface of thin-film transistor to be exposed to external environment condition and to be easy to scratch.If cause scratch, then scrape the random reflection ray in injury, make screen fuzzy thus.Form after the aluminium nitride film, preparing to form on the surface of thin-film transistor, form the oxide-film 1103 as basic unit, its thickness is 1000 to 3000

In order to form this layer oxide-film, can carry out sputter at oxygen atmosphere.In addition, also can be in oxygen atmosphere using plasma CVD decompose the deposit tetraethyl-metasilicate, to the film that forms 450 ° of-650 ℃ of annealing.

Then, using plasma CVD or LPCVD, deposition of amorphous silicon film, its thickness are 300-1500 , 500-1000 preferably

This film is carried out the photoetching Butut, make it become island shape silicon area 1104.Form silicon oxide film then, its thickness is 200-1500

500-1000 preferably

This layer silicon oxide film is also as gate insulating film.Must be especially careful when therefore, preparing this film.In this example, prepare by tetraethyl-metasilicate.By radio frequency plasma CVD,, preferably under 200-250 ℃ the substrate temperature, in oxygen atmosphere, tetraethyl-metasilicate decomposition and shallow lake are separated at 150-400 ℃.Tetraethyl-metasilicate is 1:1-1:3 with the pressure ratio of oxygen.Pressure is 0.05-0.5torr.Radio-frequency power is 100-250w.In addition, can also preferably under 200-250 ℃ the substrate temperature,, prepare this film with ozone gas at 150-400 ℃ by tetraethyl-metasilicate by low pressure chemical vapor deposition or atmospheric pressure cvd.After forming this film, in the atmosphere of oxygen or ozone, under 300-500 ℃ to laminated annealing 30-60 minute.

Then, shown in Figure 12 (A), shine laminated with the laser emission of KrF excimer, optical maser wavelength is 248nm, and pulse duration is nsec, so that make silicon area 1104 crystallization.The energy density of laser emission is 200-400mj/cm ², be preferably 250-300mj/cm ²During laser emission, substrate is heated to 300-500 ℃.The degree of crystallinity of the silicon fiml that forms by this method is by to Raman spectroscopy, at 515cm ^-1Near the quite wide spike of observation, this is different from the peak (512cm of monocrystalline silicon ^-1).Then, in hydrogen atmosphere, under 350 ℃ to laminated annealing 2 hours.

Then, form thick 2000 by electron beam evaporation The aluminium film of-5 μ m also carries out photoetching Butut formation gate electrode 1106.Silicon with 0.5-2% mixes to aluminium.It is 7 contain in the tartaric ethanedioic acid solution of 1-3% that substrate is immersed in pH value.Adopt the platinum plate as negative electrode, this grid aluminium electrode carries out anodized as anode to substrate.When the beginning of anode treatment, institute's making alive is risen to 220V with constant current.This condition was kept 1 hour, then end process.In this example, under the constant current state, suitable voltage climbing speed is 2-5v/min, in such a way, and thick 2000

Anodic oxide coating 1107 be formed (Figure 12 (B)).

Then, adopt autoregistration ion doping technology (being also referred to as plasma doping technology), utilize gate electrode as mask simultaneously, to the island of thin-film transistor shape silicon area implanting impurity ion or phosphonium ion.Adopt hydrogen phosphide as impurity gas.Dosage is 2-8 x 10 ¹⁵Ion/cm ²

Then, shown in Figure 12 (C), laminated with the laser radiation of KrF excimer, its wavelength is 248nm, and pulse duration is 20nsec, improves the silicon fiml degree of crystallinity that causes deterioration because of ion doping with this.At this moment, the energy density of laser emission is 150-400mj/cm ², 200-250mj/cm preferably ²In this method, form N type phosphorus doping district 1108 and 1109.The sheet resistance in these districts is 200-800 Ω/cm ²

Subsequently, adopt tetraethyl-metasilicate and oxygen, perhaps adopt tetraethyl-metasilicate and ozone by low pressure or atmospheric pressure cvd by plasma CVD, thick at whole surface deposition

Silicon oxide film, as interlayer insulation body 1110.Substrate temperature 150-400 ℃, be preferably 200-300 ℃.After this film forms, this layer silicon oxide film carried out mechanical polishing, make surfacing.In addition, sputtering deposit ITO and this figure of photoetching form pixel capacitors 1111 (Figure 12 (D)).

Shown in Figure 12 (E), form contact hole in the source/drain region of each thin-film transistor.Form the wiring layer 1112 and 1113 of chromium or titanium nitride, wiring layer 1113 is connected with pixel capacitors 1111.At last, in hydrogen, to laminated annealing 0.1-2 hour, finish the hydrogenation of silicon thus under 200-300 ℃.Constitute thin-film transistor by this method.A large amount of thin-film transistors of making simultaneously are by the row and column setting, thus the formation active matrix liquid crystal display.

Embodiment 9

The transistorized preparation example of membrane according to the invention as figure B shown in, at first, by reactive sputtering method, on the substrate 401 of healthy and free from worry (Corning) 7059 glass, the thick 1000-2000 of deposit

Aluminium nitride film 402.Use aluminium as target, in nitrogen and nitrogen atmosphere, carry out sputter.Wherein nitrogen content surpasses 20%, obtains to have the cover layer of thermal conductive resin thus.When sputter, pressure is 1 x 10 ^-4-1 x 10 ^-2Torr can bring forth good fruit.Deposition rate is 20-200

/ min.During deposit, substrate temperature can rise to 100-500 ℃.

Then, form thick 1000-3000

Silicon oxide film, as the oxide-film 403 that constitutes basic unit.In order to form this layer oxide-film, can in oxygen atmosphere, carry out sputter.In addition, can decompose and the deposit tetraethyl-metasilicate by plasma CVD in oxygen atmosphere, the film of formation can be 450 ℃ of-650 ℃ of annealing.

Afterwards, by plasma CVD or LPCVD deposition of amorphous silicon film, its thickness is 1000-3000

Be preferably 1000-1500

In blanket of nitrogen under 600 ℃ to laminated annealing 48 hours.The crystal silicon film that is obtained is carried out the photoetching Butut, make it become island shape silicon area 404.Silicon oxide deposition is as gate insulator 407, and its thickness is 200-1500 Be preferably 500-1000

Form thick 2000 by electron beam evaporation

The aluminium film of-5 μ m also carries out the photoetching Butut.Under the condition identical,, form gate electrode 409 and wiring layer 408 to the laminated anodized of carrying out with embodiment 8.Then, adopt autoregistration ion doping technology (be also referred to as plasma and mix up technology) to utilize gate electrode simultaneously, inject to the island of thin-film transistor shape silicon area and mix up ion or phosphonium ion, use hydrogen phosphide (PH as mask ₃) as mixing up gas.Dosage is 2-8 x 10 ¹⁵Ion/cm ²

Laminated with the laser radiation of KrF excimer, its wavelength is 248nm, and pulse duration is 20nsec, improves because of ion with this and mixes up the silicon fiml degree of crystallinity that causes deterioration.The energy density of laser emission is 150-400mj/cm ², be preferably 200-250mj/cm ²In such a way, form N type doped region 405 and 406.The sheet resistance in these districts is 200-800/cm ²(Figure 13 (A)).

Then, by plasma CVD, LPCVD or atmospheric pressure cvd, deposit thick 3000 on whole surface Silica, as interlayer insulation body 410.Selectively apply photoresist 411.Preferably apply photoresist (Figure 13 (B)) in the crosspoint of wiring layer or at contact and wiring layer connecting place.

Shown in Figure 13 (C), utilize photoresist 411 as mask, to interlayer insulation body 410, the base film layer 403 of gate insulator 407 and silica carries out etching.Although base film layer is etched, because aluminium nitride film has played protective action, so substrate can be not etched.Can obtain smooth surface (Figure 13 (C)) in such a way.

Form thick 2000

The titanium film of-5 μ m is as conductive interconnect material.This layer titanium film carried out the photoetching Butut, and formation and the wiring layer 412 and 413 that the source and the leakage of thin-film transistor link to each other selectively form ITO, make pixel capacitors 414.At last, in 1 atmospheric hydrogen, under 350 ℃,, finish laminated hydrogenation thus to the laminated annealing of making in such a way 30 minutes.Make a thin-film transistor in such a way.A large amount of thin-film transistors of making are simultaneously arranged by row and column, constituted active matrix liquid crystal display.

Embodiment 10

An example according to manufacturing thin-film transistor of the present invention is shown in Figure 14.At first, adopt reactive sputtering, on the substrate 601 of healthy and free from worry (Corning) 7059 glass, the thick 2000-4000 of deposit

Aluminium nitride film 602.Utilize aluminium as target, in nitrogen and argon atmospher, carry out sputter.Wherein nitrogen content surpasses more than 20%, can obtain to have the cover layer of thermal conductive resin.When sputter, pressure is 1 x 10 ^-4-1 x 10 ^-2The result that torr can produce.Deposition rate is 20-200

/ min.During deposit, substrate temperature can rise to 100-500 ℃.

Then, the silicon oxide deposition thickness is 1000-2000

As oxide-film 603, and constitute basic unit.In order to form this layer oxide-film, can in the oxygen environment, finish sputter.In addition, can decompose and the deposit tetraethyl-metasilicate by plasma CVD in the oxygen environment, the gained film can be 450-650 ℃ of annealing.

Then, by plasma CVD or LPCVD deposition of amorphous silicon film, thickness is 1000-3000 , be preferably 1000-1500

In nitrogen atmosphere under 600 ℃ to laminated annealing 48 hours.The crystal silicon film that obtains is carried out the photoetching Butut, form island silicon area 604.Silicon oxide deposition is as gate insulating film 605, and thickness is 200-1500

Be preferably 500-1000

Form thick 2000 by electron beam evaporation

The aluminium film of-5 μ m, and carry out the photoetching Butut.Under the condition identical,, form gate electrode 606 and wiring layer 607 (Figure 14 (A)) to the laminated anodized of carrying out with embodiment 8.

Then, adopt autoregistration ion doping technology (being also referred to as plasma doping technology), utilize gate electrode as mask simultaneously, to the island silicon area implanting impurity ion or the phosphonium ion of thin-film transistor.Use hydrogen phosphide (PH ₃) as impurity gas.Dosage is 2-8 x10 ¹⁵Ion/cm ²(Figure 14 (B)).

Silicon oxide film 603 as basic unit is carried out etching.Etch-stop is in the aluminium nitride film 602 as overcoat.Under this condition, laminated with the laser radiation of KrF excimer, its wavelength is 248nm, and pulse duration is 20nsec, improves because of ion with this and mixes up the silicon fiml degree of crystallinity that causes deterioration.The energy density of laser emission is 100-400mj/cm ², be preferably 100-150mj/cm ²Owing to contain the silicon oxide film ultraviolet radiation-absorbing of phosphorus or boron, and then mix up as the whole of embodiment 8, carry out laser annealing, need to use light laser light.In the present embodiment, if remove silicon oxide film or gate insulating film after mixing up, then only need less laser energy to get final product.This can improve the productivity ratio of laser treatment.In such a way, form N type phosphorus doped region 608 and 609.The sheet resistance in these districts is 200-800 Ω/cm ²(Figure 14 (C)).

Then, by waiting from body CVD, LPCVD or atmospheric pressure cvd, silicon oxide deposition is as interlayer insulation 610 on whole surface, and its thickness is 2000- Form thick

The aluminium film of-5 μ m is as the wiring layer material.This layer aluminium is carried out the photoetching Butut, form the wiring layer 611 and 612 that is connected with leakage with the source of thin-film transistor.As shown in the figure, wiring layer 612 intersects (Figure 14 (C)) with wiring layer 607.

At last, in 1 atmospheric hydrogen under 350 ℃, to the laminated annealing handled in such a way 30 minutes.Thus, finish laminated hydrogenation.Constitute thin-film transistor by this method.Simultaneously, doped region is mixed up, make the P channel thin-film transistor, make CMOS with boron.Typical case's mobility of N raceway groove and P channel-type is respectively 80-150cm ²/ vs and 40-100cm ²/ vs.We are verified, and the shift register that is made of these thin-film transistors is when drain voltage works in 11MHZ during for 17V.

Even long-time (about 96 hours) apply the high voltage above 20V on grid and drain region, performance also only has decline slightly.This is because the local heat that produces has been suppressed separating out at the interface and from the hydrogen atom at the interface of gate insulating film from semiconductor covering layer by very fast dissipation in the thin-film transistor.

Embodiment 11

Press step shown in Fig. 2 (A)-(E), on soda-lime glass substrate 201, form active matrix circuit.On the whole surface of substrate 201, form the dielectric film 202 that thermal conductivity is higher than silica 203.In this example, film 202 is made by aluminium nitride.Under the condition identical, form aluminium nitride film by sputter with present embodiment 8.

Then, by the mode identical, form silicon oxide film 203 as basic unit with embodiment 2.Then, by the thin-film transistor of step formation shown in Fig. 2 (E) that is similar to embodiment 2.

Embodiment 12

By as shown in figure 15 step, on the substrate 701 of healthy and free from worry (Corning) 7059 glass, the silicon fiml transistor that is formed for constituting the laser transister of peripheral circuit is used for the amorphous silicon film transistor of active matrix circuit.On substrate 701, formed the high dielectric film 725 of ratio silicon oxide 702 thermal conductivities.In the present embodiment, this film 725 is made up of transparent aluminium oxide.This pellumina 725 is under the condition identical with embodiment 8, and sputter forms.Subsequently, formed basic unit silicon oxide film 702 will be deposited to thick 20 to 200nm.After this, carry out and each identical step of embodiment 4 each step, on silicon oxide film 702, form TFT (thin-film transistor) again, shown in Figure 15 (D).

Embodiment 13

Form each step of TFT, be illustrated in Figure 16 (A)-16 (E), on dielectric substrate 901, formed the high dielectric film 925 of ratio silicon oxide 902 thermal conductivities.In the present embodiment, this film 925 is made up of aluminium nitride, and this aluminium nitride film 925 is that sputter forms under the condition identical with embodiment 8.Then, formed the silicon oxide film 902 that constitutes basic unit, subsequently, carry out with embodiment 6 each step same form TFT with each step, shown in Figure 16 (E).

Embodiment 14

Each step with Figure 17 (A)-17 (E) illustrates forms TFT.On dielectric substrate 801, form the also high dielectric film 825 of ratio silicon oxide 802 thermal conductivities.In the present embodiment, this film 825 is made up of aluminium nitride.This aluminium nitride film 825 is that sputter forms under the condition identical with 8 of enforcement.Then, form the silicon oxide film 802 that constitutes basic unit.Carry out subsequently and each identical step of embodiment 5 each step, form TFT, shown in Figure 17 (D).

Even the present invention can be used for making the TFT that a kind of long-time making alive also demonstrates high reliability.This shows, the present invention industrial be very useful.Especially, the TFT here is formed on the large tracts of land substrate, and can be used for the active array circuit or be used for drive circuit, has obtained huge industrial efficiency.

According to the present invention, can be at low temperatures, the rate that manufactures a finished product with very high produces TFT.As the various embodiments described above are described, can produce various LCD structures according to the present invention, because, by the present invention, the required electrical characteristics of setting TFT that can be random.

Though do not narrate in the various embodiments described above, the present invention can be applied to be based upon the three-dimensional IC structure on monocrystalline IC and so on the semiconductor circuit.The various embodiments described above mainly are limited to the application of the present invention in various LCD.Obviously, the present invention also can be used for other and need be produced on the dielectric substrate, in the circuit as image sensor and so on.

Claims (38)

1. method of making semiconductor device comprises:

On glass substrate, form semiconductor film, make the part of semiconductor film become channel formation region;

Form the gate insulating film of silicon oxide-containing with the mist of TEOS and oxygen-containing gas by CVD, this gate insulating film is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

To described gate insulating film annealing, its annealing region is 300 ℃ to 500 ℃; And

Near described channel formation region, form gate electrode, described gate insulating film is between gate electrode and the channel formation region.

2. the method for claim 1 is characterized in that, described gate insulating film is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

3. the method for claim 1 is characterized in that, described gate insulating film forms by the RF plasma CVD.

4. the method for claim 1 is characterized in that, the pressure ratio of TEOS and oxygen-containing gas is 1:1 to 1:3.

5. the method for claim 1 is characterized in that, and is further comprising the steps of: at least described gate insulating film and described semiconductor film are annealed in hydrogeneous atmosphere.

6. the method for claim 1 is characterized in that, and is further comprising the steps of: make laser beam irradiation to described gate insulating film, with the described semiconductor film of crystallization.

7. method as claimed in claim 6 is characterized in that, the energy density of described laser beam is 200mJ/cm ²To 400mJ/cm ²

8. method as claimed in claim 6 is characterized in that, during with laser beam irradiation, described glass substrate is heated to 300 ℃ to 500 ℃.

9. method of making semiconductor device comprises:

On glass substrate, form the basic unit of silicon oxide-containing by CVD with the mist of the TEOS and first oxygen-containing gas;

To the annealing of described basic unit, wherein, described basic unit anneals under 450 ℃ to 650 ℃ temperature range;

Form semiconductor film moving back in the basic unit that overdoes, make the part of semiconductor film become channel formation region;

Form the gate insulating film of silicon oxide-containing with the mist of the TEOS and second oxygen-containing gas by CVD, this gate insulating film is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

To described gate insulating film annealing, its annealing region is 300 ℃ to 500 ℃; And

Near described channel formation region, form gate electrode, the described gate insulating film that overdoes that moves back is between gate electrode and the channel formation region.

10. method as claimed in claim 9 is characterized in that, described gate insulating film is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

11. method as claimed in claim 9 is characterized in that, described gate insulating film forms by the RF plasma CVD.

12. method as claimed in claim 9 is characterized in that, when forming described gate insulating film, the pressure ratio of the TEOS and second oxygen-containing gas is 1:1 to 1:3.

13. method as claimed in claim 9 is characterized in that, and is further comprising the steps of: in hydrogeneous atmosphere, at least described gate insulating film and described semiconductor film are annealed.

14. method as claimed in claim 9 is characterized in that, and is further comprising the steps of: make laser beam irradiation to described gate insulating film, with the described semiconductor film of crystallization.

15. method as claimed in claim 14 is characterized in that, the energy density of described laser beam is 200mJ/cm ²To 400mJ/cm ²

16. method as claimed in claim 14 is characterized in that, during with laser beam irradiation, described glass substrate is heated to 300 ℃ to 500 ℃.

17. a method of making semiconductor device comprises:

On glass substrate, form semiconductor film, make the part of semiconductor film become channel formation region;

Form the gate insulating film of silicon oxide-containing with the mist of the TEOS and first oxygen-containing gas by CVD, this gate insulating film is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

To described gate insulating film annealing, its annealing region is 300 ℃ to 500 ℃;

Near described channel formation region, form gate electrode, described gate insulating film is between gate electrode and the channel formation region;

Form the interlayer insulation body of silicon oxide-containing with the mist of the TEOS and second oxygen-containing gas by CVD, this interlayer insulation body is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

In described interlayer insulation body, form contact hole;

On described interlayer insulation body, form pixel capacitors.

18. method as claimed in claim 17 is characterized in that, described second oxygen-containing gas is an oxygen.

19. method as claimed in claim 17 is characterized in that, described second oxygen-containing gas is an ozone.

20. method as claimed in claim 17 is characterized in that, described gate insulating film is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

21. method as claimed in claim 17 is characterized in that, described gate insulating film forms by the RF plasma CVD.

22. method as claimed in claim 17 is characterized in that, when forming described gate insulating film, the pressure ratio of the TEOS and first oxygen-containing gas is 1:1 to 1:3.

23. method as claimed in claim 17 is characterized in that, and is further comprising the steps of: in hydrogeneous atmosphere, at least described gate insulating film and described semiconductor film are annealed.

24. method as claimed in claim 17 is characterized in that, and is further comprising the steps of: make laser beam irradiation to described gate insulating film, with the described semiconductor film of crystallization.

25. method as claimed in claim 24 is characterized in that, the energy density of described laser beam is 200mJ/cm ²To 400mJ/cm ²

26. method as claimed in claim 24 is characterized in that, during with laser beam irradiation, described glass substrate is heated to 300 ℃ to 500 ℃.

27. method as claimed in claim 17 is characterized in that, described interlayer insulation body is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

28. a method of making semiconductor device comprises:

On glass substrate, form the basic unit of silicon oxide-containing by CVD with the mist of the TEOS and first oxygen-containing gas;

To the annealing of described basic unit, wherein, described basic unit anneals under 450 ℃ to 650 ℃ annealing region;

Form semiconductor film described moving back in the basic unit that overdoes, make the part of semiconductor film become channel formation region;

Form the gate insulating film of silicon oxide-containing with the mist of the TEOS and second oxygen-containing gas by CVD, this gate insulating film is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

To described gate insulating film annealing, its annealing region is 300 ℃ to 500 ℃;

Near described channel formation region, form gate electrode, described gate insulating film is between gate electrode and the raceway groove formation;

Form the interlayer insulation body of silicon oxide-containing with the mist of TEOS and the 3rd oxygen-containing gas by CVD, this interlayer insulation body is 150 ℃ to 400 ℃ at underlayer temperature and forms down;

In described interlayer insulation body, form contact hole;

On described interlayer insulation body, form pixel capacitors.

29. method as claimed in claim 28 is characterized in that, described second oxygen-containing gas is an oxygen.

30. method as claimed in claim 28 is characterized in that, described the 3rd oxygen-containing gas is an ozone.

31. method as claimed in claim 28 is characterized in that, described gate insulating film is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

32. method as claimed in claim 28 is characterized in that, described gate insulating film forms by the RF plasma CVD.

33. method as claimed in claim 28 is characterized in that, in the step that forms described gate insulating film, the pressure ratio of the TEOS and second oxygen-containing gas is 1:1 to 1:3.

34. method as claimed in claim 28 is characterized in that, and is further comprising the steps of: in hydrogeneous atmosphere, at least described gate insulating film and described semiconductor film are annealed.

35. method as claimed in claim 28 is characterized in that, and is further comprising the steps of: make laser beam irradiation to described gate insulating film, with the described semiconductor film of crystallization.

36. method as claimed in claim 35 is characterized in that, the energy density of described laser beam is 200mJ/cm ²To 400mJ/cm ²

37. method as claimed in claim 35 is characterized in that, during with laser beam irradiation, described glass substrate is heated to 300 ℃ to 500 ℃.

38. method as claimed in claim 35 is characterized in that, described interlayer insulation body is 200 ℃ to 250 ℃ at underlayer temperature and forms down.

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