US2963390A - Method of making a photosensitive semi-conductor device - Google Patents

Method of making a photosensitive semi-conductor device Download PDF

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US2963390A
US2963390A US536489A US53648955A US2963390A US 2963390 A US2963390 A US 2963390A US 536489 A US536489 A US 536489A US 53648955 A US53648955 A US 53648955A US 2963390 A US2963390 A US 2963390A
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Jr Donald C Dickson
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Hoffman Electronics Corp
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Assigned to APPLIED SOLAR ENERGY CORPORATION, A CORP. OF CA. reassignment APPLIED SOLAR ENERGY CORPORATION, A CORP. OF CA. OPTION (SEE DOCUMENT FOR DETAILS). Assignors: OPTICAL COATING LABORATORY, INC.
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Definitions

  • a semiaconductor material may comprise an intrinsic or :pure substance, such as crystalline germanium, silicon or other suitable material, in which the valence ring electrons .ofthe constituent-atoms are tightly bound-and hencesunavailable for electrical conduction, the intrinsic material being doped or contaminated with an activating substance comprising atoms distributed in and forming an integral part of the lattice structure of the intrinsic material.
  • the proportion of activating impurity to intrinsic. material may boot the order of one impurity atom for each hundred million atoms of intrinsic material.
  • Activating substances which provide excess electrons are. commonly referred to as electron donors sincethey supply electrons which are free to move within the lattice structure of the semi-conductor material.
  • Excess electron semi-conductors are commonly referred *to as comprising N-type material since electrical conduction is carried on by the flow of negatively charged electrons through the material. 7
  • each atom ofactivating material must borrow electrons'from an adjacent atom of the intrinsic material, thereby creating-what maybe referred to as ahole; that is to say, an incomplete group ofatom bonding electrons simulating the properties of a positivelycharged electron in the lattice structure of the semi-conductor material.
  • Hole creating activators are commonly called acceptormaterials since they take up electrons-from the surrounding atoms of the intrinsic material to form positive holestherein.
  • Intrinsic material activated by an acceptor substance is commonly referred towas aP-type semi-conductor since conduction therein is effected by the movement of positive holes in the material.
  • Electricalrenergy may flow .in. either direction through both types of semi-conductor material.
  • a; bodyof P-type material is joined with a body of N- typelmaterial to form therebetween what is commonly referred tons a -P-N junction,-the positive holes in the P-type material and the free electrons in the N-type material-are mutually .repelled away from the junction.
  • the. P-N- junction is theequivalent .of a
  • connection of the positive and negative sides of a source of unidirectionalelectrical potential, as a so called forward bias, respectively to the P-type and N-type sides of a P-N junction element will tend to offset the potential hill "by'driving the holesof theP-type material-and the electrons of the N-type material toward the junction, thereby allowing current flow across the junction if and when the applied potential exceeds the potential drop across the junction element, including the equivalent potential value of the junction hill.
  • a semi-conductor element embodying a PN junction may be employed as an electrical power rectifier.
  • Semi-conductor elements embodying P-N junctions may show photosensitive characteristics where a junction is disposed close toa surface adapted for exposure to light.- When light impinges upon such a junction-adjacent surface of a semi-conductor element, electron-hole pairs will be created in the semi-conductor element at the surface upon which light is impinged, such electron-hole pairs being initially under no electrical stress.
  • the junction resistance is such that substantially all of the applied potential difference appears across the junction, there being little, if any, voltage drop across the junction forming bodies of semi-condu'ctormaterial on opposite sides of'the junction.
  • the electron hole pairs created as thezresult of light applied to the element will diffuse through the semi-conductor material and some of them will come into the surface adjacent junction area.
  • the junction pairs lower the resistance of the junction area, at least temporarily, thereby causing current flow therein which will be directly proportional to the intensity of impinging light, since the number of electron-hole pairs created will be a function of the amount of light applied to the semiconductor element.
  • An important object of the present invention is to provide a photosensitive device of the character mentioned having an unusuallylarge light receiving surface, thereby affording highly sensitive light responsive characteristics.
  • Another important object of the present invention is to provide an improved photosensitive semi-conductor of .thecharacter mentioned by applying, to a body of material of selected type, an activating substance .in vaporized condition, thereby to conditionportionsof said body at and inwardly of a light receiving surface thereof as material of another type, whereby to form a P-N junction between the so conditioned surface portions of the body and the portions thereof lying inwardly of such surface portions, said junction being closely adjacent the said light receiving surface of said body; a further object being to form said body as a relatively thin layer or plate and to condition said layer in fashion forming a P-N junction thereon at a depth of the order of of an inch behind a light receiving surface of the layer; a still further object being to provide a layer of semi-conductor material having thickness of the order of of an inch and conditioned to provide a P-N junction medially between the opposite faces of the layer with P-type material on one side of the junction, and N-type material on the other; yet another object being to mount the
  • Another important object is to provide a photosensitive semi-conductor device comprising a body of silicon of selected type having portions at and inwardly of a light receiving surface thereof, treated with an activating substance to condition said portions as material of a different type, thereby forming a P-N junction between the so conditioned surface portions of the body and the portions thereof disposed inwardly of and closely adjacent light receiving surface; a further object being to form the layer of silicon of selected type upon a plate or panel of electron conducting material by vaporization and condensation of the silicon to desired depth upon the panel; yet another object being to first coat the support panel of conducting material prior to the application of the layer of semi-conducting material thereon with a thin bonding layer of a substance capable of forming ohmic connection between the support panel and the layer of semiconducting material.
  • a further object of the invention is to provide a photosensitive device comprising a relatively thin layer of N-type silicon having portions of said layer at and inwardly of a light receiving surface thereof, doped with boron, aluminum, gallium, indium, thallium or other suitable electron acceptor material, in order to constitute such doped portions of the layer as P-type material; a further object being to secure the layer of N-type silicon upon a support plate or panel of electrical conducting material such as copper, nickel, tantalum, and the like, by means of a thin bonding layer of gold doped with antimony or other bonding substance capable of forming substantially ohmic connection between the N-type silicon layer and the support panel; a still further object being to apply the bonding layer to a depth of the order of of an inch upon the support panel behind'the layer of semi-conducting material.
  • a further object of the invention is to provide a photosensitive device comprising a relatively thin layer of P-type silicon having portions of said layer at and inwardly of a light receiving surface thereof, doped with phosphorus, arsenic, antimony, bismuth or other suitable electron donor material, in order to constitute such doped portions as N-type material; a further object being to secure the layer of P-type silicon upon a support plate or panel of electrical conducting material such as copper, nickel, tantalum, and the like, by means of a thin bonding layer of aluminum or other suitable bonding substance capable of forming substantially ohmic connection between the P-type layer and thesupport panel; a still further object being to apply the bonding layer to a depth of the order of of an inch upon the support panel behind the layer of semi-conducting material.
  • Fig. 1 is a perspective view of a photosensitive semiconductor device embodying the present invention
  • Fig. 2 is an enlarged and partially sectionalized view of the device shown in Fig. 1;
  • Fig. 3 is a greatly enlarged sectional view taken substantially along the line 3-3 in Fig. 1;
  • Figs. 4 and 5 are face views of modified photosensitive semi-conductor device embodying the present invention.
  • the drawings show a photosensitive semi-conductor device 11 comprising a relatively thin layer 12 of semi-conductor material providing a P-N junction 13 between the opposite faces of the layer, one surface of said layer being preferably ohmically connected upon a support plate 14 of electrical conducting material, and the opposite surface of the layer 12 being exposed for light impingement thereon. While the broader aspects of the invention are not necessarily limited to the specific semi-conductor material of the layer 12, the invention, in its specific aspects, contemplates the use of silicon as the constituent material of the layer 12.
  • Photosensitive characteristics are imparted to the layer 12 by disposing the P-N junction 13 exceedingly close to the light receiving surface of the layer; and it is an important object of the present invention, not only to provide for the disposition of a P-N junction close to the light receiving surface of the layer, but also to provide a junction of substantial area and to form the same at a distance behind the light receiving surface of the layer that is substantially uniform throughout its entire area.
  • the support plate 14 may comprise a panel or disc having thickness of the order of A3 inch, or less.
  • the disc may be of any suitable or convenient size and configuration, a circle having diameter of the order of one inch or more being suitable for the intended purpose.
  • the layer 12, as initially applied to the base plate 14, may comprise either P-type or N-type semi-conductor material, such as silicon, the N-type material being particularly well suited for use in producing large area photosensitive devices, in accordance with the present invention.
  • the base plate 14 may conveniently comprise tantalum, copper, nickel, or other self-supporting electron conducting material.
  • a thin film of bonding material may first be applied upon the layer carrying surface of the base plate, said film of bonding material serving to form a strong mechanical bond, as well as an ohmic, or low resistance, electrical connection between the layer 12 and the support plate throughout the entire area of the supported layer.
  • the bonding layer 15 may have thickness of the order of 0.00001 inch and may be applied as by vaporization and condensation of the bonding material upon the surface of the support plate.
  • the bonding layer 15 may comprise gold doped with antimony or other suitable electron donor material; but where said layer 12 initially consists of P-type material, the bonding layer 15 may comprise aluminum or other electron acceptor type materia
  • the layer 12 of semi-conductor material may be applied as by depositing silicon of the selected type upon the film 15 to a depth of the order of 0.0002 inch.
  • the material of the layer 12 may conveniently be applied by vaporization and condensation of the selected material upon the bonding film 15, asby exposing the coated surface of the supportplate 14in an atmosphei'e comprising the selected semi-conductor material in vaporized condition for a lengthof time suflicient to build up the layer 12. to desired depth upon the coated surface 'ofthe support plate.
  • the layer-12 After the layer-12 "has thus been applied upon, and-in ohmic contact with, the supportplate 14, it may be treated to alter the type of its material at and to a desired depth inwardly ofiiitslightreceiving. surface, as in the o r portions 16 of the layer, the inner portions 17 of the layer remaining unchanged, whereby to form the P-N junction 13 between the layer portions 16 and 17 which are thus constituted as laminae of material of unlike type, on opposite sides of the P-N junction 13.
  • it may be treated with an activating substance other than, and different from, that which is distributed in the material, in order to determine its initial type.
  • the layer portions 16 at and inwardly of its light receiving surface may be conditioned with boron, aluminum, indium, gallium, thallium, or other suitable electron acceptor substance, in order to constitute the layer portions 16 as P-type semi-conductor material.
  • the portions 16 may be treated with arsenic, antimony, bismuth, or other electron donor substance, in order to constitute the layer portions 16 as N-type semi-conductor material.
  • the layer 12 preferably, consists initially of N-type silicon embodying arsenic, antimony, bismuth, or other electron donor substance, and the surface portions 16 being treated with boron or other electron acceptor substance, to constitute the same as P-type semi-conductor material.
  • the activating or conditioning substance employed to determine the character of the material in the layer p ortions 16 may be applied to the light receiving surface of the layer, and caused to penetrate to a desired depth therein by exposing the layer, in situ, on the support plate 14, in an atmosphere consisting of the selected activating substance in vaporized condition, the plate supported layer being retained in such atmosphere and hence soaked in the vaporized activating substance during a period of sufficient duration to obtain penetration of the activating substance to a desired depth at and beneath the light receiving surface of the layer. It will be apparent, of course, that the P-N junction 13 Will be established between the layer portions 16 and 17 of contrasting type.
  • electrode means 18 may be electrically connected with the layer portion 16, while a connection terminal 19, such as a threaded post, may be soldered, or otherwise electrically connected, with the base plate 14.
  • the terminal 19 may conveniently be secured to the one side of the support plate 14 remote from the layer 12, the terminal being preferably attached at the medial portions of the support plate.
  • the electrode means 18 may conveniently comprise nickel, electroplated to a depth of the order of 0.0005 inch, preferably in the form of an annular ring 20 deposited on, and in electrical contact with, the peripheral edges of the layer portion 16, such ring affording means for attachment as by soldering or otherwise with a connection conductor 21 for connecting the layer portion 16 in external circuitry.
  • the foregoing arrangement for making electrical contact with the layer portion 16 is an important feature of the invention, since it is not easy to connect a conductor directly with a thin layer of material such as the portion 16, the thickness of which is of the order of 0.0001 inch.
  • the device described may be employed as a photosensitive device by mounting the same in position to receive the impingement of light upon the outwardly facing surface of the layer portion 16. Where light impinges up,o n,,such surfa e, lectr n ql rair wi1 1.,.b.
  • ring like electrode 20 shown in Fig. 1 is adequate formost purposes, itmayube desirable to .provide the electrode in "the form of a laminous network 22 of conductive material applied upon the light receiving surface of the layer portion 16, which network may comprise a ring-like portion 20', similar to the ring-like electrode 20 of the device as shown in Figs. 1, 2 and 3, and a plurality of preferably substantially equally spaced apart, line-like fingers 23 of electrical conducting material, electrically interconnected and connected with the ring-like portion 20, said line-like fingers being interspersed in spaced apart relation substantially throughout the surface of the layer 16, within the ring-like electrode portion 20'. As shown more particularly in Fig.
  • the fingers 23 may be of curved configuration and may be electrically interconnected and connected with the ring-like electrode portion 20 by means of radially extending connecter portions 24. As shown in Fig. 5, the fingers 23 of electrical conducting material may be relatively straight and connected directly with the ring-like portion 20'. Any other preferred pattern or arrangement of spaced fingers may, of course, be employed.
  • the fingers 23 and the connecting portions 24 may comprise the same material that is used in forming the ring-like electrode 20 and the electrode portion 20', which material may be applied by electroplating the same in a desired pattern upon the light receiving surface of the layer portion 16 simultaneously with the application of the ring-like portion 20'.
  • the foregoing procedure for the fabrication of a photosensitive semi-conductor device permits the fabrication of a device having any desired, precisely determined area for receiving the impingement of light.
  • the foregoing procedure furthermore, allows for exceedingly precise control, not only of the thickness of the layer 12, but also the spacement of the junction 13, with respect to the light receiving surface of the layer 12.
  • the resulting device is of exceedingly rugged character which cannot be destroyed by any usual shocks or jars to which electronic equipment is ordinarily subjected in service.
  • a light sensitive semi-conductor device which consists in applying a thin layer of bonding material to a surface of a support plate of electrical conducting material, then depositing, by vaporization and condensation, a layer of crystalline semiconductor material of selected conductivity type throughout and having a thickness of approximately 0.0002 inch upon said layer of bonding material, said bonding material being of the type to form an ohmic contact between said layer of semi-conductor material and said support plate, thereafter exposing said layer of semiconductor material to the action of an activating substance in vaporized condition to penetrate the layer with the substance at and to a desired depth approximating 0.0001 inch inwardly of the plate-remote surface of said layer, whereby to constitute the portion of said layer of semi-conductor material at and inwardly of said plateremote surface as material of different conductivity type,

Description

Dec. 6, 1960 D. c. DICKSON, JR 2,963,390
METHOD OF MAKING A PHOTO-SENSITIVE SEMI-CONDUCTORDEVICE Filed Sept. 26, 1955 ALD c. DICK ,JR.
ATTORNEYS IN VE 3 WWMQWJQM Y United States Patent METHUD OF MAKING A PHOTOSENSITIV E SEMI-CGNDU CTOR "DEVICE Donald C. Dickson, Jr., Prospect Heights, Ill., assignor to Hoffman Electronics Corporation, Los Angeles, Califl, acorporation of California Filed Sept. 26, 1955, Ser. No. 536,489
23Claims. (Cl. 148-1.-5)
The present invention relates, in general, to electronics andzhas more particular reference tophoto'sensitive electron flow =devices employing semi-conductor material, the invention pertaining specificallyto an improved-photosensitivedevice embodying a P N junction.
A semiaconductor material .may comprise an intrinsic or :pure substance, such as crystalline germanium, silicon or other suitable material, in which the valence ring electrons .ofthe constituent-atoms are tightly bound-and hencesunavailable for electrical conduction, the intrinsic material being doped or contaminated with an activating substance comprising atoms distributed in and forming an integral part of the lattice structure of the intrinsic material. The proportion of activating impurity to intrinsic. material may boot the order of one impurity atom for each hundred million atoms of intrinsic material.
Suitable activating substances for activating intrinsic semi-conductor material comprise atoms containing either a=-greater or lesser number of valence electrons than the constituent atoms of the intrinsic material. Where the atoms of the activating substance comprise more valence electrons than are associated with the atoms of the intrinsic material, the excess electrons may circulate freely in and through the crystal structure of the semi-conductor material and are hence available for electrical conduction purposes. Activating substances which provide excess electrons are. commonly referred to as electron donors sincethey supply electrons which are free to move within the lattice structure of the semi-conductor material. Excess electron semi-conductors are commonly referred *to as comprising N-type material since electrical conduction is carried on by the flow of negatively charged electrons through the material. 7
Where the atoms of the activating substance embody fewersvalence electrons than are associated with the'atoms of :.the intrinsic substance, each atom ofactivating material must borrow electrons'from an adjacent atom of the intrinsic material, thereby creating-what maybe referred to as ahole; that is to say, an incomplete group ofatom bonding electrons simulating the properties of a positivelycharged electron in the lattice structure of the semi-conductor material. Hole creating activators are commonly called acceptormaterials since they take up electrons-from the surrounding atoms of the intrinsic material to form positive holestherein. Intrinsic material activated by an acceptor substance is commonly referred towas aP-type semi-conductor since conduction therein is effected by the movement of positive holes in the material.
Electricalrenergy may flow .in. either direction through both types of semi-conductor material. When, however, a; bodyof P-type material is joined with a body of N- typelmaterial to form therebetween what is commonly referred tons a -P-N junction,-the positive holes in the P-type material and the free electrons in the N-type material-are mutually .repelled away from the junction. In this. connection, the. P-N- junction :is theequivalent .of a
2,963,390 Patented Dec. 6, 1960 unidirectional potential source having negative and positive sides respectively connected with the P-type and N- type materials on opposite sides of the junction, thereby constituting the junction as a potential hill, past which electrical energy may flow more easily in one direction than the other. If, for example, the positive and negative sides of a source of unidirectional electrical potential be connected respectively with the N-type and P-type ends of a P-N junction element, in fashion commonly referred to as reverse bias, such potential source will merely increase the potential hill, by drawing the valence electrons and holes mutually awayfrom the junction, and, consequently no current flowmay take place across the P-N junction.
On the .otherhand, connection of the positive and negative sides of a source of unidirectionalelectrical potential, as a so called forward bias, respectively to the P-type and N-type sides of a P-N junction element, will tend to offset the potential hill "by'driving the holesof theP-type material-and the electrons of the N-type material toward the junction, thereby allowing current flow across the junction if and when the applied potential exceeds the potential drop across the junction element, including the equivalent potential value of the junction hill. Accordingly, a semi-conductor element embodying a PN junction may be employed as an electrical power rectifier.
Heretofore semi-conductor elements embodying P-N junctions have been produced by initially growing a crystal ingot of intrinsic material to desired size in the presence of an activator of one' kind, an electron donor material, for example, to thereby constitute the resulting crystalline substance as N-type semi-conductor material. Thereafter growth of the crystal ingot may be continued in the presence of an activating substance of the other kind, such as an electron acceptor material, to thereby constitute the subsequently grown portions of the ingot as P-type material. Insuch an ingot, the P-N junction extends between the N-type and P-type portions of the ingot body.
Semi-conductor elements embodying P-N junctions may show photosensitive characteristics where a junction is disposed close toa surface adapted for exposure to light.- When light impinges upon such a junction-adjacent surface of a semi-conductor element, electron-hole pairs will be created in the semi-conductor element at the surface upon which light is impinged, such electron-hole pairs being initially under no electrical stress. The junction resistance is such that substantially all of the applied potential difference appears across the junction, there being little, if any, voltage drop across the junction forming bodies of semi-condu'ctormaterial on opposite sides of'the junction. As a consequence, the electron =hole pairs created as thezresult of light applied to the element will diffuse through the semi-conductor material and some of them will come into the surface adjacent junction area. By so doing, the junction pairs lower the resistance of the junction area, at least temporarily, thereby causing current flow therein which will be directly proportional to the intensity of impinging light, since the number of electron-hole pairs created will be a function of the amount of light applied to the semiconductor element.
An important object of the present invention is to provide a photosensitive device of the character mentioned having an unusuallylarge light receiving surface, thereby affording highly sensitive light responsive characteristics.
Another important object of the present invention is to provide an improved photosensitive semi-conductor of .thecharacter mentioned by applying, to a body of material of selected type, an activating substance .in vaporized condition, thereby to conditionportionsof said body at and inwardly of a light receiving surface thereof as material of another type, whereby to form a P-N junction between the so conditioned surface portions of the body and the portions thereof lying inwardly of such surface portions, said junction being closely adjacent the said light receiving surface of said body; a further object being to form said body as a relatively thin layer or plate and to condition said layer in fashion forming a P-N junction thereon at a depth of the order of of an inch behind a light receiving surface of the layer; a still further object being to provide a layer of semi-conductor material having thickness of the order of of an inch and conditioned to provide a P-N junction medially between the opposite faces of the layer with P-type material on one side of the junction, and N-type material on the other; yet another object being to mount the layer upon a supporting base plate of suitable electrical conducting material such as copper, nickel or tantalum, preferably having a thickness of the order of A5" or less, the layer of semi-conductor material being electrically connected in ohmic fashion on said base plate throughout a surface of said layer; yet another object being to ohmically connect the layer of semi-conductor material upon the support base prior to the exposure of the base remote, light receiving surface of the layer to the vaporized activating substance for the formation of the P-N junction therein.
Another important object is to provide a photosensitive semi-conductor device comprising a body of silicon of selected type having portions at and inwardly of a light receiving surface thereof, treated with an activating substance to condition said portions as material of a different type, thereby forming a P-N junction between the so conditioned surface portions of the body and the portions thereof disposed inwardly of and closely adjacent light receiving surface; a further object being to form the layer of silicon of selected type upon a plate or panel of electron conducting material by vaporization and condensation of the silicon to desired depth upon the panel; yet another object being to first coat the support panel of conducting material prior to the application of the layer of semi-conducting material thereon with a thin bonding layer of a substance capable of forming ohmic connection between the support panel and the layer of semiconducting material.
A further object of the invention is to provide a photosensitive device comprising a relatively thin layer of N-type silicon having portions of said layer at and inwardly of a light receiving surface thereof, doped with boron, aluminum, gallium, indium, thallium or other suitable electron acceptor material, in order to constitute such doped portions of the layer as P-type material; a further object being to secure the layer of N-type silicon upon a support plate or panel of electrical conducting material such as copper, nickel, tantalum, and the like, by means of a thin bonding layer of gold doped with antimony or other bonding substance capable of forming substantially ohmic connection between the N-type silicon layer and the support panel; a still further object being to apply the bonding layer to a depth of the order of of an inch upon the support panel behind'the layer of semi-conducting material.
A further object of the invention is to provide a photosensitive device comprising a relatively thin layer of P-type silicon having portions of said layer at and inwardly of a light receiving surface thereof, doped with phosphorus, arsenic, antimony, bismuth or other suitable electron donor material, in order to constitute such doped portions as N-type material; a further object being to secure the layer of P-type silicon upon a support plate or panel of electrical conducting material such as copper, nickel, tantalum, and the like, by means of a thin bonding layer of aluminum or other suitable bonding substance capable of forming substantially ohmic connection between the P-type layer and thesupport panel; a still further object being to apply the bonding layer to a depth of the order of of an inch upon the support panel behind the layer of semi-conducting material.
The foregoing and numerous other important objects, advantages and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawings, discloses preferred embodiments of the invention.
Referring to the drawings:
Fig. 1 is a perspective view of a photosensitive semiconductor device embodying the present invention;
Fig. 2 is an enlarged and partially sectionalized view of the device shown in Fig. 1;
Fig. 3 is a greatly enlarged sectional view taken substantially along the line 3-3 in Fig. 1; and
Figs. 4 and 5 are face views of modified photosensitive semi-conductor device embodying the present invention.
To illustrate the invention, the drawings show a photosensitive semi-conductor device 11 comprising a relatively thin layer 12 of semi-conductor material providing a P-N junction 13 between the opposite faces of the layer, one surface of said layer being preferably ohmically connected upon a support plate 14 of electrical conducting material, and the opposite surface of the layer 12 being exposed for light impingement thereon. While the broader aspects of the invention are not necessarily limited to the specific semi-conductor material of the layer 12, the invention, in its specific aspects, contemplates the use of silicon as the constituent material of the layer 12. Photosensitive characteristics are imparted to the layer 12 by disposing the P-N junction 13 exceedingly close to the light receiving surface of the layer; and it is an important object of the present invention, not only to provide for the disposition of a P-N junction close to the light receiving surface of the layer, but also to provide a junction of substantial area and to form the same at a distance behind the light receiving surface of the layer that is substantially uniform throughout its entire area.
In order to accomplish the objectives of the present invention, the support plate 14 may comprise a panel or disc having thickness of the order of A3 inch, or less. The disc may be of any suitable or convenient size and configuration, a circle having diameter of the order of one inch or more being suitable for the intended purpose. The layer 12, as initially applied to the base plate 14, may comprise either P-type or N-type semi-conductor material, such as silicon, the N-type material being particularly well suited for use in producing large area photosensitive devices, in accordance with the present invention. In either case, the base plate 14 may conveniently comprise tantalum, copper, nickel, or other self-supporting electron conducting material.
In order to secure the layer 12 upon the base plate 14, a thin film of bonding material may first be applied upon the layer carrying surface of the base plate, said film of bonding material serving to form a strong mechanical bond, as well as an ohmic, or low resistance, electrical connection between the layer 12 and the support plate throughout the entire area of the supported layer. The bonding layer 15 may have thickness of the order of 0.00001 inch and may be applied as by vaporization and condensation of the bonding material upon the surface of the support plate. Where the layer 12 initially consists of N-type semi-conductor material, the bonding layer 15 may comprise gold doped with antimony or other suitable electron donor material; but where said layer 12 initially consists of P-type material, the bonding layer 15 may comprise aluminum or other electron acceptor type materia After application of the bonding film, the layer 12 of semi-conductor material may be applied as by depositing silicon of the selected type upon the film 15 to a depth of the order of 0.0002 inch. The material of the layer 12 may conveniently be applied by vaporization and condensation of the selected material upon the bonding film 15, asby exposing the coated surface of the supportplate 14in an atmosphei'e comprising the selected semi-conductor material in vaporized condition for a lengthof time suflicient to build up the layer 12. to desired depth upon the coated surface 'ofthe support plate.
After the layer-12 "has thus been applied upon, and-in ohmic contact with, the supportplate 14, it may be treated to alter the type of its material at and to a desired depth inwardly ofiiitslightreceiving. surface, as in the o r portions 16 of the layer, the inner portions 17 of the layer remaining unchanged, whereby to form the P-N junction 13 between the layer portions 16 and 17 which are thus constituted as laminae of material of unlike type, on opposite sides of the P-N junction 13. In order to so change the type of material in the outer portions, or lamina 16 of the layer 12, it may be treated with an activating substance other than, and different from, that which is distributed in the material, in order to determine its initial type. Accordingly, where the layer 12 comprises N-type semi-conductor material, the layer portions 16 at and inwardly of its light receiving surface may be conditioned with boron, aluminum, indium, gallium, thallium, or other suitable electron acceptor substance, in order to constitute the layer portions 16 as P-type semi-conductor material. Conversely, where the layer 12 initially comprises P-type semi-conductor material, the portions 16 may be treated with arsenic, antimony, bismuth, or other electron donor substance, in order to constitute the layer portions 16 as N-type semi-conductor material. The layer 12, preferably, consists initially of N-type silicon embodying arsenic, antimony, bismuth, or other electron donor substance, and the surface portions 16 being treated with boron or other electron acceptor substance, to constitute the same as P-type semi-conductor material.
The activating or conditioning substance employed to determine the character of the material in the layer p ortions 16 may be applied to the light receiving surface of the layer, and caused to penetrate to a desired depth therein by exposing the layer, in situ, on the support plate 14, in an atmosphere consisting of the selected activating substance in vaporized condition, the plate supported layer being retained in such atmosphere and hence soaked in the vaporized activating substance during a period of sufficient duration to obtain penetration of the activating substance to a desired depth at and beneath the light receiving surface of the layer. It will be apparent, of course, that the P-N junction 13 Will be established between the layer portions 16 and 17 of contrasting type.
In order to provide for electrical connection of the layer portions 16 and 17 in external electrical circuits, electrode means 18 may be electrically connected with the layer portion 16, while a connection terminal 19, such as a threaded post, may be soldered, or otherwise electrically connected, with the base plate 14. The terminal 19 may conveniently be secured to the one side of the support plate 14 remote from the layer 12, the terminal being preferably attached at the medial portions of the support plate.
The electrode means 18 may conveniently comprise nickel, electroplated to a depth of the order of 0.0005 inch, preferably in the form of an annular ring 20 deposited on, and in electrical contact with, the peripheral edges of the layer portion 16, such ring affording means for attachment as by soldering or otherwise with a connection conductor 21 for connecting the layer portion 16 in external circuitry. The foregoing arrangement for making electrical contact with the layer portion 16 is an important feature of the invention, since it is not easy to connect a conductor directly with a thin layer of material such as the portion 16, the thickness of which is of the order of 0.0001 inch.
The device described may be employed as a photosensitive device by mounting the same in position to receive the impingement of light upon the outwardly facing surface of the layer portion 16. Where light impinges up,o n,,such surfa e, lectr n ql rair wi1 1.,.b.
hole pairslwilltdiffuse-through the semi-conductor materialof the layer portion 16 andinto the junction area, thereby lowering the resistance of the junction and allowing current tlow there'through, in amount substantially proportional to the intensity of impinging light.
While the ring like electrode 20 shown in Fig. 1 is adequate formost purposes, itmayube desirable to .provide the electrode in "the form of a laminous network 22 of conductive material applied upon the light receiving surface of the layer portion 16, which network may comprise a ring-like portion 20', similar to the ring-like electrode 20 of the device as shown in Figs. 1, 2 and 3, and a plurality of preferably substantially equally spaced apart, line-like fingers 23 of electrical conducting material, electrically interconnected and connected with the ring-like portion 20, said line-like fingers being interspersed in spaced apart relation substantially throughout the surface of the layer 16, within the ring-like electrode portion 20'. As shown more particularly in Fig. 4 of the drawings, the fingers 23 may be of curved configuration and may be electrically interconnected and connected with the ring-like electrode portion 20 by means of radially extending connecter portions 24. As shown in Fig. 5, the fingers 23 of electrical conducting material may be relatively straight and connected directly with the ring-like portion 20'. Any other preferred pattern or arrangement of spaced fingers may, of course, be employed. The fingers 23 and the connecting portions 24 may comprise the same material that is used in forming the ring-like electrode 20 and the electrode portion 20', which material may be applied by electroplating the same in a desired pattern upon the light receiving surface of the layer portion 16 simultaneously with the application of the ring-like portion 20'.
The foregoing procedure for the fabrication of a photosensitive semi-conductor device permits the fabrication of a device having any desired, precisely determined area for receiving the impingement of light. The foregoing procedure, furthermore, allows for exceedingly precise control, not only of the thickness of the layer 12, but also the spacement of the junction 13, with respect to the light receiving surface of the layer 12. The resulting device is of exceedingly rugged character which cannot be destroyed by any usual shocks or jars to which electronic equipment is ordinarily subjected in service.
It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.
The invention is claimed as follows:
1. The method of making a light sensitive semi-conductor device, which consists in applying a thin layer of bonding material to a surface of a support plate of electrical conducting material, then depositing, by vaporization and condensation, a layer of crystalline semiconductor material of selected conductivity type throughout and having a thickness of approximately 0.0002 inch upon said layer of bonding material, said bonding material being of the type to form an ohmic contact between said layer of semi-conductor material and said support plate, thereafter exposing said layer of semiconductor material to the action of an activating substance in vaporized condition to penetrate the layer with the substance at and to a desired depth approximating 0.0001 inch inwardly of the plate-remote surface of said layer, whereby to constitute the portion of said layer of semi-conductor material at and inwardly of said plateremote surface as material of different conductivity type,
a r 7 and to form a P-N junction between the substance penetrated and remaining portions of said layer. 1
2. The method in accordance with claim 1, in which said bonding material is applied by vaporization and condensation to a thickness approximating 0.00001 inch on 5 the surface of the support plate.
References Cited in the file of this patent UNITED STATES PATENTS 2,567,970 Scalf et a1 Sept. 18, 1951 10 8 Pearson "Feb, 24, 1953 Dunlap July 7, 1953 Haynes Oct. 12, 1954 Conrad May 3, 1955 Hewlett Feb. 5, 1957 FOREIGN PATENTS Belgium Nov. 14, 1952

Claims (1)

1. THE METHOD OF MAKING A LIGHT SENSITIVE SEMI-CONDUCTOR DEVICE, WHICH CONSISTS IN APPLYING A THIN LAYER OF BONDING MATERIAL TO A SURFACE OF A SUPPORT PLATE OF ELECTRICAL CONDUCTING MATERIAL, THEN DEPOSITING, BY VAPORIZATION AND CONDENSATION, A LAYER OF CRYSTALLINE SEMICONDUCTOR MATERIAL OF SELECTED CONDUCTIVITY TYPE THROUGHOUT AND HAVING A THICKNESS OF APPROXIMATELY 0.0002 INCH UPON SAID LAYER OF BONDING MATERIAL, SAID BONDING MATERIAL BEING OF THE TYPE TO FORM AN OHMIC CONTACT BE TWEEN SAID LAYER OF SEMI-CONDUCTOR MATERIAL AND SAID SUPPORT PLATE, THEREAFTER EXPOSING SAID LAYER OF SEMICONDUCTOR MATERIAL TO THE ACTION OF AN ACTIVATING SUBSTANCE IN VAPORIZED CONDITION TO PENETRATE THE LAYER WITH THE SUBSTANCE AT AND TO A DESIRED DEPTH APPROXIMATING 0.0001 INCH INWARDLY OF THE PLATE-REMOTE SURFACE OF SAID LAYER, WHEREBY TO CONSITUTE THE PORTION OF SAID LAYER OF SEMI-CONDUCTOR MATERIAL AT AND INWARDLY OF SAID PLATEREMOTE SURFACE AS MATERIAL OF DIFFERENT CONDUCTIVITY TYPE, AND TO FORM A P-N JUNCTION BETWEEN THE SUBSTANCE PENETRATED AND REMAINING PORTIONS OF SAID LAYER.
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Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011104A (en) * 1959-07-31 1961-11-28 Watanabe Yasushi Semiconductor diodes
US3138495A (en) * 1961-07-28 1964-06-23 Texas Instruments Inc Semiconductor device and method of manufacture
US3175091A (en) * 1962-07-02 1965-03-23 Ibm Photoconductor material and stabilization thereof at low temperature
US3182198A (en) * 1962-03-12 1965-05-04 Hughes Aircraft Co Semi-conductor infrared radiation detecting and converting apparatus
US3184823A (en) * 1960-09-09 1965-05-25 Texas Instruments Inc Method of making silicon transistors
US3214654A (en) * 1961-02-01 1965-10-26 Rca Corp Ohmic contacts to iii-v semiconductive compound bodies
US3233111A (en) * 1962-05-31 1966-02-01 Union Carbide Corp Silicon whisker photocell with short response time
US3317733A (en) * 1963-05-10 1967-05-02 Ibm Radiation scanner employing rectifying devices and photoconductors
US3379559A (en) * 1963-12-20 1968-04-23 American Can Co Glass container having metal oxide and resin coatings
DE1273717B (en) * 1963-06-20 1968-07-25 Stanley Electric Co Ltd Arrangement of photo resistors for light meters of cameras
US3462311A (en) * 1966-05-20 1969-08-19 Globe Union Inc Semiconductor device having improved resistance to radiation damage
US3497698A (en) * 1968-01-12 1970-02-24 Massachusetts Inst Technology Metal insulator semiconductor radiation detector
US3514847A (en) * 1966-05-10 1970-06-02 Gen Dynamics Corp Process for making photoconductive matrices
US3541679A (en) * 1967-05-18 1970-11-24 Nasa Method of attaching a cover glass to a silicon solar cell
US3579060A (en) * 1969-03-21 1971-05-18 Gen Electric Thyristor with improved current and voltage handling characteristics
US3903428A (en) * 1973-12-28 1975-09-02 Hughes Aircraft Co Solar cell contact design
US3934143A (en) * 1972-11-10 1976-01-20 Siemens Aktiengesellschaft Detector for ionizing radiation
JPS52133169U (en) * 1976-04-02 1977-10-08
US4209347A (en) * 1979-05-04 1980-06-24 Rca Corporation Mounting for solar cell
US4228315A (en) * 1979-05-04 1980-10-14 Rca Corporation Solar cell grid patterns
US4361717A (en) * 1980-12-05 1982-11-30 General Electric Company Fluid cooled solar powered photovoltaic cell
US4361950A (en) * 1980-03-24 1982-12-07 Exxon Research & Engineering Co. Method of making solar cell with wrap-around electrode
US4395636A (en) * 1980-12-24 1983-07-26 Regents Of The University Of California Radiation imaging apparatus
US4703168A (en) * 1985-07-22 1987-10-27 Princeton Applied Research Corporation Multiplexed wedge anode detector
US20080092942A1 (en) * 2006-10-13 2008-04-24 The Boeing Company Front contact design for high-intensity solar cells and optical power converters

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE514927A (en) * 1952-01-22
US2567970A (en) * 1947-12-24 1951-09-18 Bell Telephone Labor Inc Semiconductor comprising silicon and method of making it
US2629800A (en) * 1950-04-15 1953-02-24 Bell Telephone Labor Inc Semiconductor signal translating device
US2644852A (en) * 1951-10-19 1953-07-07 Gen Electric Germanium photocell
US2691736A (en) * 1950-12-27 1954-10-12 Bell Telephone Labor Inc Electrical translation device, including semiconductor
US2707319A (en) * 1952-12-31 1955-05-03 Stromberg Carlson Co Semi-conducting device
US2780569A (en) * 1952-08-20 1957-02-05 Gen Electric Method of making p-nu junction semiconductor units

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2567970A (en) * 1947-12-24 1951-09-18 Bell Telephone Labor Inc Semiconductor comprising silicon and method of making it
US2629800A (en) * 1950-04-15 1953-02-24 Bell Telephone Labor Inc Semiconductor signal translating device
US2691736A (en) * 1950-12-27 1954-10-12 Bell Telephone Labor Inc Electrical translation device, including semiconductor
US2644852A (en) * 1951-10-19 1953-07-07 Gen Electric Germanium photocell
BE514927A (en) * 1952-01-22
US2780569A (en) * 1952-08-20 1957-02-05 Gen Electric Method of making p-nu junction semiconductor units
US2707319A (en) * 1952-12-31 1955-05-03 Stromberg Carlson Co Semi-conducting device

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3011104A (en) * 1959-07-31 1961-11-28 Watanabe Yasushi Semiconductor diodes
US3184823A (en) * 1960-09-09 1965-05-25 Texas Instruments Inc Method of making silicon transistors
US3214654A (en) * 1961-02-01 1965-10-26 Rca Corp Ohmic contacts to iii-v semiconductive compound bodies
US3138495A (en) * 1961-07-28 1964-06-23 Texas Instruments Inc Semiconductor device and method of manufacture
US3182198A (en) * 1962-03-12 1965-05-04 Hughes Aircraft Co Semi-conductor infrared radiation detecting and converting apparatus
US3233111A (en) * 1962-05-31 1966-02-01 Union Carbide Corp Silicon whisker photocell with short response time
US3175091A (en) * 1962-07-02 1965-03-23 Ibm Photoconductor material and stabilization thereof at low temperature
US3317733A (en) * 1963-05-10 1967-05-02 Ibm Radiation scanner employing rectifying devices and photoconductors
DE1273717B (en) * 1963-06-20 1968-07-25 Stanley Electric Co Ltd Arrangement of photo resistors for light meters of cameras
US3379559A (en) * 1963-12-20 1968-04-23 American Can Co Glass container having metal oxide and resin coatings
US3514847A (en) * 1966-05-10 1970-06-02 Gen Dynamics Corp Process for making photoconductive matrices
US3462311A (en) * 1966-05-20 1969-08-19 Globe Union Inc Semiconductor device having improved resistance to radiation damage
US3541679A (en) * 1967-05-18 1970-11-24 Nasa Method of attaching a cover glass to a silicon solar cell
US3497698A (en) * 1968-01-12 1970-02-24 Massachusetts Inst Technology Metal insulator semiconductor radiation detector
US3579060A (en) * 1969-03-21 1971-05-18 Gen Electric Thyristor with improved current and voltage handling characteristics
US3934143A (en) * 1972-11-10 1976-01-20 Siemens Aktiengesellschaft Detector for ionizing radiation
US3903428A (en) * 1973-12-28 1975-09-02 Hughes Aircraft Co Solar cell contact design
JPS52133169U (en) * 1976-04-02 1977-10-08
US4209347A (en) * 1979-05-04 1980-06-24 Rca Corporation Mounting for solar cell
US4228315A (en) * 1979-05-04 1980-10-14 Rca Corporation Solar cell grid patterns
FR2455800A1 (en) * 1979-05-04 1980-11-28 Rca Corp SOLAR CELL, PARTICULARLY SILICON, THE CONSTRUCTION OF WHICH AVOIDS THE HARMFUL EFFECTS OF DILATION DIFFERENCES ON CELL INTEGRITY
US4361950A (en) * 1980-03-24 1982-12-07 Exxon Research & Engineering Co. Method of making solar cell with wrap-around electrode
US4361717A (en) * 1980-12-05 1982-11-30 General Electric Company Fluid cooled solar powered photovoltaic cell
US4395636A (en) * 1980-12-24 1983-07-26 Regents Of The University Of California Radiation imaging apparatus
US4703168A (en) * 1985-07-22 1987-10-27 Princeton Applied Research Corporation Multiplexed wedge anode detector
US20080092942A1 (en) * 2006-10-13 2008-04-24 The Boeing Company Front contact design for high-intensity solar cells and optical power converters

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