CA2548366C

CA2548366C - Coated article with ir reflecting layer and method of making same

Info

Publication number: CA2548366C
Application number: CA2548366A
Authority: CA
Inventors: Jochen Butz; Anton Dietrich; Uwe Kriltz; Richard Blacker
Original assignee: Centre Luxembourgeois de Recherches pour le Verre et la Ceramique CRVC SARL; Guardian Industries Corp
Current assignee: Guardian Europe SARL; Guardian Glass LLC
Priority date: 2005-06-07
Filing date: 2006-05-25
Publication date: 2012-03-13
Anticipated expiration: 2026-05-25
Also published as: ES2626536T3; US7597962B2; EP1734019B1; PL1734019T3; EP1734019A3; CA2548366A1; EP1734019A2; US20060275613A1

Abstract

A coated article is provided with at least one infrared (IR) reflecting layer (e.g,. silver based). In certain example embodiments, silicon nitride, zinc oxide, and an oxide of Ni and/or Cr are provided under the IR reflecting layer. It has been found that improved thermal stability may be realized upon beat treatment. In certain example instances, the silicon nitride may be replaced with tin oxide.

Description

TITLE OF THE INVENTION

COATED ARTICLE WITH IR REFLECTING LAYER AND METHOD OF
MAKING SAME

[0001] This application relates to a coated article including at least one infrared (IR) reflecting layer of a material such as silver or the like. In certain example non-limiting embodiments, the provision of a layer comprising silicon nitride in a particular area have been found to improve the thermal stability of the coated article (e.g., upon tempering or the like). Moreover, in certain example non-limiting embodiments, a layer comprising zinc oxide is provided under the IR reflecting layer in order to improve, qualities thereof, and a layer comprising a material such as an oxide of Ni and/or Cr is provided between the IR reflecting layer and the zinc oxide inclusive layer in order to improve thermal stability upon heat treatment (e.g., thermal tempering) and to substantially preserve performance following such heat treatment.
In certain example non-limiting embodiments, the zinc oxide inclusive layer is formed by sputtering a ceramic target, which has been found to improve properties of the IR
reflecting layer. In view of the above, it is possible to permit the coated article for example to realize improved properties such as one or more of thermal stability upon heat treatment, emittance, U-value, and/or specific resistivity. Coated articles herein may be used in the context of insulating glass (IG) window units, or in other suitable applications such as monolithic window applications, laminated windows, and/or the like.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF
THE INVENTION

(0002] Coated articles are known in the art for use in window applications such as insulating glass (IG) window units, vehicle windows, monolithic windows, and/or the like. In certain example instances, designers of coated articles often strive for a combination of high visible transmission, substantially neutral color, low emissivity (or emittance), low sheet resistance (RS), low U-values in the context of IG
window units, and/or low specific resistivity. High visible transmission and substantially neutral color may permit coated articles to be used in applications where I

these characteristics are desired such as in architectural or vehicle window applications, whereas low-emissivity (low-E), low sheet resistance, and low specific resistivity characteristics permit such coated articles to block significant amounts of IR radiation so as to reduce for example undesirable heating of vehicle or building interiors.

[0003] Consider a typical coated article with the following layer stack. This coated article is suitable for use in an IG (insulation glass) window unit.
For the coated article listed below, the coating includes layers that are listed from the glass substrate outwardly.

Layer Thickness (A) Glass TtCx 140 A
5noz 100 A
ZnAIO7, 70 A
Ag 11$ Ai NiCrOO 2o A
SnOt 223 A
SiN1, 160 A

[0004] The silver (Ag) layer of the above coated article has a thickness of angstroms (A) and a sheet resistance (R$) of 4.6 ohms/square. This translates into a specific resistivity (R, multiplied by thickness of the IR reflecting layer) for the silver IR reflecting layer of 5.43 micro-ohms.cm.

[0005] While the aforesaid specific resistivity (SR) of the silver 1R
reflecting layer is adequate in many situations, it would be desirable to improve upon the same.
For example, if the above coated article is heat treated (e.g., thermally tempered), it does not have good thermal stability. In other words, such heat treatment (HT) causes optical properties of the coated article (e.g., one or more of a*, b*, L*, haze) to substantially change in an undesirable manner. If the a*, b* and/or L* values change too much upon HT of the coated article, then the coated article is said to be thermally unstable since it looks much different after HT than before HT. Moreover, if MLT Regina 1/13/2010 9:25 PAGE 006/015 Fax Server artisttirity w&ert abed rnaisunca (R,) gal up too much 4 = RT, thee the pm*oct is also mad OD be rhams[Iy mullah.
Q00 1 U.S. Patent Document 20O5it104246D
discloses a layer stack that is suitable in many different harm ices. Wiese Use zinc oxide layer contacts the underside of the silver A se&cdng layer. h ham been found that When the zinc oxide directly owtaexs the bottom side of the aiilver, in certain instances the haze and/or sheet teateece of the coating use too much upon FIT.
(0l67t fit view of the above, it will be erppreciated that there exists a need iA
the an for a coated article t chores a coating which has good t ime/
properties (ag, easisaivity hence and sheet taiaraece), good optical properties (e.g.. ga=.
b+' and/or IA). and which has such good thermal and opt cal pupertiea following heat treatment such as tbamai tt nipedng. Certain ezauipla vn bodimenss of Oils javinn ion relate to a coated article which palmier one or mote of these advantages to be reallaed.
[0008] In certain example embodiments of this invention, it has soothingly, been found that the provision of a layer stack inckeling the following sequence of laye;s. moving away bow the glass aubetrtgs, is adV6UqpMW (a) a layer of or including silicon nitride. (b) a layer of or including zinc oxide, (c) a layer of or Including an oxide of Ni and/or Cr, and (d) in TQ reflecting Layer. This sequence of layers permits the coated article to tethered hi pavedthermaal smabikty. Thus, the -cartel artialda color. haste. mrniusnce and sheet tnisturce do not ehwlpin an undesirable ma ner d ft to teat 12MICAat (F For examphs the 1 e and/or shout mAs lance does not nee atuentiatly (bat may decrease) upon HP, and/or the coated article cue lot becomes trio buy due to HT. In certain example omboditu at layers of or including titanium oxide (and possibly tin aetido) may be provided harder and coaracdng the toyer camaprising siLcon auricle.
(00691 In other example embodiments of this invertrton. it has eueprisingly been found that the following sequence of layer is advantapoua; (a) a layer of or including tin oxide. (b) a layer of or including zinc oxide. (c) a layer of or including an oxide of Ni and/or t: r. tad (d) an fit reflecting layer fag., silver inclusive layer).
This sequence of layers permits the coated article to realized improved thermal PAGE 6115 * RCVD AT 111312010 10:35:50 AM (Eastern Standard Times *
SVR:FO000315 * DNIS:3907 * CSID:MLT Regina * DURATION (mm-ss):10-54 stability. Thus, the coated article's color and haze do not change in an undesirable manner due to HT. For example, the a*, b* and/or L* values do not change too much upon HT, and/or the coated article does not becomes too hazy due to HT.

[00101 In certain example embodiments of this invention, the zinc oxide inclusive layer may be formed by sputtering a ceramic target. It has been found that implementing a zinc oxide inclusive layer formed using a ceramic target, beneath a layer comprising an oxide of Ni and/or Cr, yields an improvement in the quality of the overlying silver inclusive IR reflecting layer. This structure has also been surprisingly found to provide a greater degree of thermal stability during HT
compared to the use of zinc oxide alone as the seed layer under the silver.

[0011] In certain example embodiments of this invention, it is especially surprising that such advantages can be realized in a single IR reflecting layer coating (e.g., single silver coating) that is also able to realize, when used in an IG
(insulating glass) unit, a U-value of no greater than 1.25 W/(m2K), more preferably no greater than 1.20 W/(m2K), even more preferably no greater than 1.15 W/(m2K), and most preferably no greater than 1.10 W/(m2K).

[0012] In certain example embodiments of this invention, there is provided a heat treated coated article including a coating supported by a glass substrate, the coating comprising. a dielectric layer, a layer comprising silicon nitride; a layer comprising zinc oxide over and directly contacting the layer comprising silicon nitride; a layer comprising an oxide of Ni and/or Cr over and directly contacting the layer comprising zinc oxide; an infrared (IR) reflecting layer comprising silver on the glass substrate, located over and directly contacting the layer comprising an oxide of Ni and/or Cr; another layer comprising an oxide of Ni and/or Cr located over and directly contacting the IR reflecting layer comprising silver, a layer comprising a metal oxide located over and directly contacting the another layer comprising the oxide of Ni and/or Cr; and a layer comprising silicon nitride located over the layer comprising the metal oxide.

[0013] In other example embodiments of this invention, there is provided a coated article including a coating supported by a glass substrate, the coating comprising, from the Mass substrate outwardly: a layer comprising silicon nitride or tin oxide; a layer comprising zinc oxide over and directly contacting the layer comprising silicon nitride or tin oxide; a layer comprising an oxide of Ni and/or Cr over and directly contacting the layer comprising zinc oxide; an infrared (1R) reflecting layer comprising silver over and directly contacting the layer comprising an oxide of Ni and/or Cr, and a dielectric layer.

[0014] In other example embodiments of this invention, there is provided a method of mating a coated article, the method comprising: providing a glass substrate; forming a layer comprising silicon nitride or tin oxide on the glass substrate; sputtering a ceramic target comprising zinc and oxygen in an atmosphere including at least an inert gas in order to form a layer comprising zinc oxide on the glass substrate over and directly contacting the layer comprising silicon nitride or tin oxide; forming a layer comprising an oxide of Ni and/or Cr on the glass substrate over and directly contacting the layer comprising zinc oxide; forming an infrared (IR) reflecting layer comprising silver on the glass substrate over and directly contacting the layer comprising an oxide of Ni and/or Cr; and forming a dielectric layer over at least the IR reflecting layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIGURE 1 is a cross sectional view of a coated article according to an example embodiment of this invention.

[0016] FIGURE 2 is a cross sectional view of part of an insulating glass (IG) window unit including the coated article of Fig. 1 (or Fig. 3) according to an example embodiment of this invention.

[0017] FIGURE 3 is a cross sectional view of a coated article according to another example embodiment of this invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE
INVENTION
[0018] Referring now to the drawings in which like reference numerals indicate like parts throughout the several views.

[0019] Coated articles herein may be used in applications such as monolithic windows, IG window units, vehicle windows, and/or any other suitable application that includes single or multiple substrates such as glass substrates.

(0020] In certain example embodiments of this invention, there is provided a coating for a coated article, such that the coating has good thermal properties (e.g., emissivity/emittance and sheet resistance), good optical properties (e.g., a*, b'" and/or L*), and has such good thermal and optical properties following heat treatment (HT) such as thermal tempering, heat bending, heat strengthening, or the like.
Certain example embodiments of this invention relate to a coated article which permits one or more of these advantages to be realized.

[0021] In certain example embodiments of this invention, it has surprisingly been found that the provision of a layer stack including the following sequential layers, moving from the glass substrate outwardly: (a) layer comprising silicon nitride, (b) layer comprising zinc oxide over and contacting the layer comprising silicon nitride, (c) a layer comprising an oxide of Ni and/or Cr over and contacting the layer comprising zinc oxide, and (d) an IR reflecting layer, e.g., comprising or consisting essentially of silver, located over and contacting the layer comprising the oxide of Ni and/or Cr. This sequence of layers permits the coated article to realize improved thermal stability. Thus, the coated article's color, haze, ernittance and sheet resistance do not change in an undesirable manner due to heat treatment (HI).
For example the emittance and/or sheet resistance does not rise substantially (but may decrease) upon HT, and/or the coated article does not become too hazy due to HT. In certain example embodiments, a dielectric layer (e.g., of or including an oxide of -titanium) may be provided under the above-listed sequence of layers so as to be between the sequence and the glass substrate. In certain other example embodiments, a layer of or including tin oxide may be provided between the layer comprising titanium oxide and the layer (a) of the sequence. In still further example embodiments, the layer (a) of the sequence may instead be of or comprise tin oxide.
[0022] In certain example embodiments of this invention, the sequence also surprisingly permits the IR reflecting layer (e.g., silver inclusive layer) to have a specific resistivity (SR) of no greater than 5.0, more preferably no greater than 4.8,

6 and even more preferably no greater than 4.6 micro-ohms.cm, and possibly no greater than 4.2 following HT. Such low SR values permit U-values and emittance of the coating to be lowered given a particular thickness for the IR reflecting layer(s).
Typically, for the same silver material, a lower emissivity requires more silver and thus less transmission. However, a lower specific resistivity allows a lower sheet resistance for the same transmission - which is typically a good thing since one may use less silver for the same performance.

[0023] Fig. 1 is a cross sectional view of a coated article according to an example embodiment of this invention. The coated article includes glass substrate 1 (e.g., clear, green, bronze, or blue-green glass substrate from about 1.0 to 10.0 mm thick,'more preferably from about 1.0 mm to 6.0 nirn thick), and a multi-layer coating (or layer system) provided on the substrate either directly or indirectly. As shown in Fig. 1, the coating 25 comprises dielectric layer 3, dielectric layer 5 of or including silicon nitride (e.g., Si3Na, or some other suitable stoichiometry), zinc oxide inclusive layer 7 (e.g., ZnO,, where "x" is from 1 to 3, more preferably about 2; or ZnAIO,,), bottom contact layer 8 of or including an oxide of Ni and/or Cr (e.g., NiCrO,,), IR
(infrared) reflecting layer 9 including or of silver, gold, or the like, upper contact layer I1 of or including an oxide of Ni and/or Cr (e.g., NiCrO, ), metal oxide inclusive layer 13 (e.g., an oxide of tin), and dielectric layer 15 of or including a material such as silicon nitride and/or silicon oxynitride which may in certain example instances be a protective overcoat. Other layers and/or materials may also be provided in certain example embodiments of this invention, and it is also possible that certain layers may be removed or split in certain example instances. Moreover, one or more of the layers discussed above may be doped with other materials in certain example embodiments of this invention.

[0024] In monolithic instances, the coated article includes only one substrate such as glass substrate 1 (see Fig. 1). However, monolithic coated.articles herein may be used in devices such as IG window units for example. Typically, as shown in Fig.
2, an IG window unit may include two spaced apart substrates 1 and 2, with a gap 4 defined therebetween. Example IG window units are illustrated and described, for example, in U.S. Patent Nos. 5,770,321, 5,800,933, 6,524,714, 6,541,084 and US

7 MLT Regina 1/13/2010 9:25 PAGE 007/015 Fax Server 2E3iDt5O711, An example 10 window uok as abown to E& 2 ma)r irrclade~ tarelurmpk.
the coated glass subatrale I dm m in Pig. I coded m another gm abetrara 2 vita spaaec(s). sealan(s) or the like with a pp 4 being def ned terabaween. Tide pp between the substrates in 10 writ embodmuft may in omtaln famines be Blied with agaa mob as mpn (Ar). As manfale 10 mil may aompam s pair of spaced spat substantially dear gsaaa subauaws each about 4 mm thick one of which is coated with a oodd4 25 bweia in canals ezanlpie instances, where the gap 4 between the a6ska t may be from about 5 to 30 an. man poa6aably from about W to 23 mrn, std mast preferably about 16 mm. In certain example instances, the coating 25 may be paniriaed on the aide of the frier glass srAtraaa I facing the pp (aWnaugb the coating may be oA the order nbalaaa is aenbe Aram tivo rAodtmeata). StIll twinning to Trig. 2, in certain example 10 unit ambodianemts of this invssneo.
the proposes, a pal of 4 mm char gla s sabitntea spaced apsat by 16 tree, with Ar gas in dos gap) has all-rdm also graattr tinro 1.25 Wl(m$), amens pntenbly no psi than 120 Wl(m even mole preferably no greater than U5 W1(m3S). and mast peferahiy no gta er than 1.10 W!(mt ).. am after the coral abets has bow anbJecte4 to optleml 1ff such as sampetisg. V-Vahan is aaassaged in aoootdsooc with EN 673.

[0025] The bottom dielectric layer 3 may be of or iaclode dram m oxide in carat eau i ieembeftma efthie dm. Thettoattooe oxides of layer3 Iesyfa certain exampoia inalanssbo rtp[taastod by Ti0,. abets x is from IS to ZS.
moat preferably about 2Ø The titanium oxide may be deposited via sputretiag or the W x be dlils+anr asabo&wcat& Ta certain aaaoaipla hstma"i. dtetnawie layer 3 may be as index of reftaceioa (a), at 550 stn, of at least 2Ø more preersbly of at leant 2. 1.
and possibly from about 2.3 to 26 wham the layer is of c loclades otsmltntt oxide. In certain eaabodimeets of this invention, the thick eras of tstmitnn oxide in clusivve layer 3 is coaraoired seas to allow a= aadlar b= color values (erg.. uaaiaaive, frim side reflectim aaYot gins side reflective) to be fairly neutral O.L. close to MM) aadlor detitabie. Other msteials maybe need in s8dltsOA t0 or instead of burr oxide is

8 PAGE 7115 RCVD AT 111312010 10:35:50 AM [Eastern Standard Time] * SVR:F0000315 * DNIS:3907 * CSID:MLT Regina * DURATION (mm-ss):10-54 certain example instances. In certain alternative embodiments, the Ti in oxide layer 3 may be replaced with another metal.

[0026] Silicon nitride inclusive layer 5 is provided over at least dielectric layer 3. The layer 5 of or including silicon nitride is advantageous in that it permits thermal stability of the coating to be improved upon HT, since the silicon nitride acts as a so-called barrier against diffusion of certain materials during HT. Thus, color shifts can be reduced by using silicon nitride as or in layer 5.

[0027] Dielectric layer 7 is of or includes zinc oxide (e.g., ZnO). The zinc oxide of layer(s) 7 may contain other materials as well such as Al (e.g., to form ZnAIO,,) in certain example embodiments. For example, in certain example embodiments of this invention, zinc oxide layer 7 may be doped with from about 1 to 10% Al (or B), more preferably from about 1 to 5% Al (or B), and most preferably about 2 to 4% Al (or B). The use of zinc oxide 7 under the silver in layer 9 allows for an excellent quality of silver to be achieved. In certain example embodiments (e.g., to be discussed below) the zinc oxide inclusive sub-seed layer 7 may be formed via sputtering a ceramic ZnO inclusive rotatable magnetron sputtering target. It has been found that the use of the ceramic target (e.g., of ZnO, which may or may not be doped with Al, F or the like) allows for a high quality of silver to be provided thereby resulting in a lower emissivity coating.

[0028] In an effort to obtain a low emissivity (or emittance) low-E coating, one tries to ensure that the 1R reflecting layer (e.g., silver layer 9) is as close to bulk properties as possible. This is often achieved by sputtering a "seed" layer on which it is possible to deposit and grow a perfected silver layer. An example typical seed layer is zinc oxide that is sputtered from a Zn metal target in an oxygen inclusive atmosphere. All of the oxygen for the seed layer thus comes from the oxygen gas in the sputtering chamber(s). However, sputtering the zinc oxide layer in a highly oxygenated atmosphere can lead to gaseous crosstalk contamination of an adjacent silver layer that is sputtered in an adjacent chamber(s), which can degrade the quality of the silver layer thereby leading to an increased emissivity and the coating as a whole.

9 [0029) In order to address this problem, it has been found in certain example embodiments of this invention that the zinc oxide inclusive layer 7 can be formed by sputtering a ceramic magnetron target (e.g., a target of ZnO, ZnAIO, or the like). The ratio of Zn:O in the ceramic target may be about 1:1 in certain example embodiments, but it may instead be sub stoichiometric in other example embodiments of this invention. It has been found that the use of such a ceramic target to form zinc oxide layer 7 allows for a higher quality of silver to be formed in IR reflecting layer 9 even though another layer separates layers 7 and 9 - this is particularly surprising since the technique for forming a layer one layer removed from the IR reflecting layer affects the emissivity properties thereof. In other words,. it has been found that implementing a zinc oxide inclusive layer 7 formed using a-ceramic target, beneath a layer comprising an oxide of Ni and/or Cr, yields an improvement in the quality of the silver inclusive IR reflecting layer 9. This structure has also been surprisingly found to provide a greater degree of thermal stability during HT compared to the use of zinc oxide alone as the seed layer under the silver. It is noted that the zinc oxide inclusive target(s) and the resulting layer may be doped with a non-metal such as F
and/or B in certain example embodiments of this invention.

[0030]. While the Zn:O in the ceramic target may be stoichiometric in certain example embodiments, at least one substoichiometric ceramic target comprising ZnO"
(e.g., where 0.25:5 x < 0.99, more preferably 0.50:5 x:5 0.97, and even more preferably 0.70 < x _< 0.96) may instead be used in sputter-depositing a zinc oxide inclusive layer 7 under the contact layer 8. The term "substoichiometric"
means that "x" is less than 1.0 in the case of ZnO, for example. In certain example embodiments of this invention, the substoichiometric nature of the ZnO, inclusive ceramic target for forming layer 7 causes the ceramic target to be more conductive, thereby reducing or eliminating the need for metal dopant(s) in the target 2. In particular, with no metal doping, a substoichiometric ZnO. inclusive ceramic target is able to realize improved sputtering yields and faster sputtering rates compared to a stoichiometric ZnO
ceramic target. This is highly advantageous as will be appreciated by those of skill in the art.
In certain example embodiments of this invention, no dopants are needed for substoichiometric ZnO, inclusive ceramic target(s) used in forming layer 7.
However, in certain example embodiments of this invention, a substoichiometric ZnO., inclusive ceramic target is doped with a non-metal such as F and/or B
(or alternatively a metal such as Al or the like). F and/or B when used as dopants increase the electrical conductivity of the target, which may be needed in certain situations where x is close to 1.0 even while the target is still slightly substoichiometric. In certain example embodiments of this invention, the ceramic target may be doped so as to include from about 0.5 to 5.0% F and/or B, more preferably from about 0.5 to 3% F and/or B (atomic %). In certain alternative embodiments of this invention, a stoichiometric ZnO ceramic target may be doped with from about 0.5 to 5.0% F and/or B, more preferably from about 0.5 to 3% F
and/or B. In certain example embodiments, the target may be doped with from about 0.5 to 10.0% boron. The increase in conductivity caused by the doping of the target with F and/or B (or Al) may also lead to an increase in the IR reflection of the resulting coating in certain example embodiments of this invention. If not enough F
and/or B is provided, the target may suffer with respect to conductivity in certain situations, and if too much F and/or B is provided in the target film growth and functionality would become undesirable since too much F and/or B would end up in the sputter-deposited film and the adjacent silver would have undesirable properties.
It is noted that the amounts of fluorine and/or boron in the target sputtering material tend to also end up in the resulting zinc oxide inclusive layer on the substrate in like amounts. The conductivity of the target or cathode mainly arises from dopant (e.g., B
and/or F), and/or oxygen vacancy. However, if the dopant concentration is too high, the excessive dopants in the film may act as defects and reduce conductivity.
So, an optimized dopant concentration in the target is desired in certain example non-limiting situations.

[00313 Such ceramic zinc oxide/suboxide sputtering target(s) may be used to sputter-deposit ZnO layer 7 in a low oxygen environment (i.e., a low amount of oxygen gas is required in the sputtering chamber or bay where the target(s) is located) using either AC or DC sputtering. In certain embodiments, both oxygen and argon gas are introduced into the sputtering chamber housing the ceramic target via respective gas sources. In certain example embodiments of this invention, no more than about 40%, more preferably no more than about 30%, and most preferably no more than about 20% of the total gas (e.g., argon plus oxygen) in the sputtering tl MLT Regina 1/13/2010 9:25 PAGE 008/015 Fax Server chamber including the ceramic tact is oxygen when the optloost subakichicimetew ceramic target(s) is used, in edditian to the oxygen bas in the chamber. Me ref index of the gas in the sppttaing chamber may be m last gas each is argon or the like.
Due to the low peroestye of Os gas, the depttdatias of silver p ropetties in rho iR
ea&ecting layer(s) can be rodttced doe to less tiog otc roastalit.
loom] infrared (IR) ref eering layer 9 is preferably subeasdally or entirely metallic andfo COB&ctive, and may comprise or cme st esseaiialty of silver (AS).
gold. or any other suitable IR reftect;ttg material. 1k redacting layer 9 helps allow the mating to have low E smoke food sofas control duracteistiat stick ss low err times, low street resiiu rocs and so fem. The 1R dec tip layermay, however, be slightly os ida:ed in ceruincmbodimen s of ttda imVenttose.
( ! The lower and npparcontar t layers 8 andfor 11 may be of orisdude an oxide of Ni arxVor Cr. in certain exampis embodiments, lower =dog taper contact layers 8.11 may be of or include nickel (Ni) oxide, ctntrm iumfchmme (Cr) oxide. or a idelml alloy oxide such as nickel chrome, oxide (MCrOj, or otber ennoble inatnial(aj.
The use of, forexnimplo, AGOõ in this layer(s) it allows dozehibty to be itagwved.
The NiCOO% layer(s) S, 11 may be fully oxidized in cesta L embodmenu of this invendos (i.e., rally Adchiomctric), or aitcmatively may only be par'tfagy oxidized sttbstoiehiometric (before sndllor after HT). Ts ceRain instances. the M10%
layer 8, 11 m y be st foal shoat S1)% oxit>sriod Canter ityes(s) 8,11(e g, of nor including ate oxide of r andlor Cr) may or may not be osidruioo graded in dilibreat er odimsata cit his invemltion. Oxidation grading memo that die degree of oxidation in the layer chmges through the thiCSaiess of the layer so that tar exarnplo a contact JAM
maybe greried so as to be fees oxfthyed at the contact interface with the intmed;ately adjacent IAR araectiog layer 9 than at a parka of t w oowtact layer(s) bather or mesdtnost 4iataetlints,the imme iately edjaceat 1R s+ nits layer. Ikatslpaotts of vatiotos types of oxidation graded contact layers are set forth in U.S. Parent No.
6476,349.
Contact layer(s) 8, 11 (e.g-, of or including to oxtde u( M andlbr Cr) may or may not be continuous in dtfgxeot era botfrmett of this isreation aquas the entire W oe$aoxing layer 9.

PAGE 8115 * RCVD AT 111312010 10:35:50 AM [Eastern Standard Time] *
SVR:F0000315 * DNIS:3907 * CSID:MLT Regina * DURATION (mm-ss):10-54 [00341 While zinc oxide is often used as a contact layer, it has surprisingly been found that the provision of layer 8 of or including an oxide of Ni and/or Cr between the zinc oxide of layer 7 and the silver of layer 9 results in a coating which realizes improved (i.e., lower) emissivity and/or sheet resistance after HT.
Without layer 8 comprising an oxide of Ni and/or Cr between the zinc oxide and the silver, experiments have shown that the coating will have too high of a haze and/or sheet resistance value following HT. Thus, the use of the following sequence of immediately adjacent layers has been found to be surprisingly beneficial: (a) layer 5 comprising silicon nitride, (b) layer 7 comprising zinc oxide over and contacting the layer comprising silicon nitride, (c) layer 8 comprising an oxide of Ni and/or Cr over and contacting the layer comprising zinc oxide, and (d) an IR reflecting layer 9.
[0035] Dielectric layer 13 may be of or include a metal oxide such as tin oxide in certain example embodiments of this invention. Metal oxide inclusive layer 13 is provided for antireflection purposes, and also improves the emissivity of the coated article and the stability and efficiency of the manufacturing process. The tin oxide layer 13 may be doped with other materials such as nitrogen in certain example embodiments of this invention.

[0036] Dielectric layer 15, which may be an overcoat in certain example instances, may be of or include silicon nitride (e.g., Si3N4 or other suitable stoichiometry) or any other suitable material in certain example embodiments of this invention such as silicon oxynitnde. Optionally, other layers may be provided above layer 15. Layer 15 is provided for durability purposes, and to protect the underlying layers. In certain example embodiments, layer 15 may have an index of refraction-(n) of from about 1.9 to 2 .2, more preferably from about 1.95 to 2.05.

[00373 Other layer(s) below or above the illustrated coating 25 may also be provided. Thus, while the layer system or coating is "on" or "supported by"
substrate 1 (directly or indirectly), other layer(s) may be provided therebetween. Thus, for example, the coating of Fig. 1 may be considered "on" and "supported by" the substrate 1 even if other layer(s) are provided between layer 3 and substrate 1.
Moreover, certain layers of the illustrated coating may be removed in certain embodiments, while others may be added between the various layers or the various layer(s) may be split with other layer(s) added between the split sections in other embodiments of this invention without departing from the overall spirit of certain embodiments of this invention. For example and without limitation, layer 13 may be removed in certain example situations.

[0038] While various thicknesses may be used in different embodiments of this invention, example thicknesses and materials for the respective layers on the glass substrate I in the Fig. 1 embodiment are as follows, from the glass substrate outwardly (e.g., the Al content in the zinc oxide layer 7 may be from about 1-

10%, more preferably from about 1-3% in certain example instances):

Table 1 (Example Materials/Thicknesses; Fig. I Embodiment) Layer Preferred Range (A) More Preferred (A) Example (A) TiO. (layer 3) 30-200 A 40-95 A 67 A
SixNy (layer 5) 20-300 A 60-160 A in A
ZnAIOx (layer 7) 10-200 A 40-120 A 72 A
NiCrO,, (layer 8) 10-90 A 20-60 A 38 A
Ag (layer 9) 50-250A 80-1 so A 127 A
NiCrO1 (layer 11) 10-80 A 20-70 A 48 A
SnO2 (layer 13) 40-400 A 90-200 A 134 A
SixNy (layer 15) 50-750 A 150-4W A 304 A
(0039] In certain example embodiments of this invention, coated articles herein (e.g., see Fig. 1) may have the following low-E (low emissivity), solar and/or optical characteristics set forth in Table 2 when measured monolithically, following heat treatment (e.g., thermal tempering). The specific resistivity (SR) is of the silver IR reflecting layer 9.

Table 2: Low-FJSolar Characteristics (Monolithic; HI') Characteristic General More Preferred Most Preferred Rs (ohms/sq.): <= 5.0 <= 3.8 <= 3.4 Ag SR (microohms.cm): <= 5.0 <= 4.5 <= 4.2 Eo: <= 0.10 <= 0.05 <= 0.038 Tõj, (%): >= 70 >= 80 >= 85 Haze: <= 0.2 <=0.1 <= 0.08 [0040] Moreover, coated articles including coatings according to certain example embodiments of this invention have the following optical characteristics (e.g., when the coating(s) is provided on a clear soda lime silica glass substrate 1 from 1 to 10 mm thick, preferably about 4 mm thick). In Table 3, all parameters are measured monolithically, before and/or after HT. It is noted that the AE*
values in the table below are due to the HT (i.e., a function of a*, b*, and L* changes due to HT
as known in the art).

Table 3: Example Optical Characteristics (Monolithic) Characteristic General More Preferred T,,;S (or TY)(Ill. C, 2 deg.): >= 70% >= 80% (or >= 85%) a*t (Ill. C, 2 ): -2.5 to +1.0 -2.0 to 0.0 b*t (111. C, 2 ): -1.0 to +6.0 0.0 to +4.0 L*t: >=90 >=93 RfY (Ili. C, 2 deg.): 1 to 7% 1 to 6%
a*f (Ill. C, 2 ): -5.0 to +4.0 -1.5 to +3.0 b*f (111. C, 2 ): -14.0 to +10.0 -10.0 to 0 L*t: 22-30 25-30 AE*:
RSY (Ill. C, 2 deg.): 1 to 11% 1 to 10%
a*g (Ill. C, 2 ): -5.0 to +4.0 -1.5 to +2.0 b*s (Ill. C, 2 ): -14.0 to +10.0 -12.0 to 0 L*g: 27-40 30-37 EE* (film side reflective): <= 4.0 <= 3.0 BE* (traasmissive): <= 4.0 <= 3.0 [0041] Moreover, coated articles including coatings according to certain example embodiments of this invention have the following optical characteristics when the coated article is an IG unit in certain example embodiments (e.g., for purposes of reference, when the coating is provided on a clear soda lime silica glass substrate 1 from I to 10 mm thick, preferably about 4 mm thick) on surface #3 of an IG window unit, following HT. It is noted that U-value is measured in accordance with EN 673.

Table 4: Example Optical Characteristics (10 Unit - HT) Characteristic General More Preferred T,,;, (or TY)(I11. C, 2 deg.): >= 70% >= 75%
a*t (Ill. C, 2 ): -4.5 to +1.0 -3.5 to 0.0 b*= (Ill. C. 2 ): -1.0 to +4.0 0.0 to 3.0 R õ Y (111. C, 2 deg.): <=14% <--12%
a*m (Ill. C, 2 ): -3.0 to +3.0 -2 to +2.0 b*011, (Ill. C, 20): -10.0 to +10.0 -6.0 to 0 R;ns;deY (111. C, 2 deg.): <=15% <=13%
a*i ,;de (Ill. C, 2 ): -5.0 to +4.0 -1.5 to +3.0 b*iWdc (111. C, 2 ): -14.0 to +10.0 -10.0 to 0 U-value (IG)(W/(m1K)): <= 1.25 <=1.15 (or <= 1.10) [0042) Fig. 3 is a cross sectional view of another example embodiment of this invention. The Fig. 3 embodiment is similar to that of Fig. I (and see tables above for characteristics), except that additional layer 4 of or including tin oxide is provided under the silicon nitride inclusive layer 5. The tin oxide layer 4 is located between and contacting the silicon nitride layer 5 and the titanium oxide layer 3 in certain example embodiments. The performance of this stack is similar to that of the Fig. 1 stack discussed above, in that it is fully temperable and displays good thermal stability, undergoing no significant degradation of performance during baking procedures.

[0043) In yet another example embodiment of this invention, the Fig. 1 embodiment may be modified by using tin oxide instead of silicon nitride for layer 5.
While such a coating is somewhat similar with respect to stability, it does suffer with respect to an increase in normal emissivity after HT (e.g., around 0.05, instead of about 0.038 for an example of the Fig. I embodiment).

EXAMPLE
[0044] The following example is provided for purposes of example only, and is not intended to be limiting. The following Example was made via sputtering so as to have approximately the layer stack set forth below, from the clear glass substrate outwardly. The listed thicknesses are approximations:

Table 5: Layer Stack for Example Layer Thickness Glass Substrate 4 mm TiOx 250,k Si3N4 10 A
ZnAIO8, 80A
Micro, 10 'k Ag 1001 NiCrO, 30,k Sn02 160 A
Si3N4 300 A

[0045] The silver layer 9 was sputtered using two silver planar targets, and using gas flows including Ar and Kr, where much more Ar than Kr was used. The titanium oxide layer 3 was sputtered using two Ti inclusive targets in atmosphere including Ar and 0 gases. The silicon nitride layers 5 and 15 were sputtered using SiAI targets in atmosphere including Ar and N gases. The NiCrOx layers 8 and

11 were sputtered using NiCr targets in atmosphere including Ar and oxygen gases.
The zinc oxide layer 7 was sputtered using a ceramic ZnO target in an atmosphere including Ar gas and a fairly small amount of oxygen gas. The tin oxide layer 13 was sputtered using three Sn targets in atmosphere including Ar, 0 and N gases.
After being sputter deposited onto the glass substrate, the coated article of the Example had the following characteristics, measured monolithically (measured in the center of the coated article).

Table 6: Characteristics of Example (Monolithic - no HT) Characteristic Example Visible Trans. (T,,;, or TY)(I11. C 2 deg.): 81.7%
a* -2.0 b* 2.8 L* 92.4 Glass Side Reflectance (RY)(lll C, 2 deg.): 7.1%
a* 0.2 b* -9.0 L* 31.9 Film Side Reflective (FY)(Ill. C. 2 deg.): 4.3 a* 4.5 b* -9.7 L* 24.7 R, (ohms/square): 4.6 [0046] Then, the coated article of the example was heat treated by thermally tempering it. via a twelve minute cycle with the four zones of the furnace at 580, 700, 700 and 640 degrees C, respectively. Following AT, the coated article had the following characteristics:

Table 7; Characteristics of Example (Monolithic - after HT) Characteristic Example Visible Trans. (Tõu or TY)(I11. C 2 deg.): 86.8%
a* -2.1 -b* 2.4 L* 94.7 Glass Side Reflectance (RY)(Ii1 C, 2 deg.): 6.7%
a* 3.2 b* -9.5 L* 31.1 Film Side Reflective (FY)(1]l. C, 2 deg.): 5.1%
a* 4.7 b* -8.3 L* 269 Rs (ohms/square): 3.3 Emissivity (normal): 0.038 Haze: 0.07 AE* (film side reflective): 2.62 AE* (transmissive): 2.34 [00471 Comparative examples were made and tested. For example, a comparative example that was similar to the Example above except that it did not include NCrOx layer 8. This comparative example had a much higher emissivity following HT than did the Example above, thereby indicating the unexpected results associated with certain example embodiments of this invention. Another example was made and tested, and was similar to the Example above except that it used tin oxide instead of silicon nitride for layer 5. This example also had a higher emissivity following HT compared to the Example above.

[00481 The low film side reflective and transmissive AE* values, due to the heat treatment, is indicative of thermal stability upon heat treatment.

[00491 When the aforesaid monolithic Example was used in an IG window unit, the 1G window unit had a U-value of about 1.1 W/(m2K).

[00501 While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A heat treated coated article including a coating supported by a glass substrate, the coating comprising:

a dielectric layer;

a layer comprising silicon nitride;

a layer comprising zinc oxide over and directly contacting the layer comprising silicon nitride;

a layer comprising an oxide of Ni and/or Cr over and directly contacting the layer comprising zinc oxide;

an infrared (IR) reflecting layer comprising silver on the glass substrate, located over and directly contacting the layer comprising an oxide of Ni and/or Cr;

another layer comprising an oxide of Ni and/or Cr located over and directly contacting the IR reflecting layer comprising silver;

a layer comprising a metal oxide located over and directly contacting the another layer comprising the oxide of Ni and/or Cr;

a layer comprising silicon nitride located over the layer comprising the metal oxide; and wherein the layer comprising zinc oxide is formed using a ceramic target comprising zinc oxide so that the IR reflecting layer comprising silver has a specific resistivity (SR) of no greater than 4.2 microohms.cm and the coating has a sheet resistance of no greater than 3.8 ohms/square, and wherein there is only one IR reflecting layer comprising silver in the coating.

2. The coated article of claim 1, wherein the dielectric layer comprises titanium oxide.

3. The coated article of claim 1, wherein the dielectric layer comprises tin oxide.

4. The coated article of claim 1, further comprising a layer comprising tin oxide provided between the dielectric layer and the layer comprising silicon nitride.

5. The coated article of claim 1, wherein the coating has a sheet resistance (R s) of no greater than 3.4 ohms/square.

6. The coated article of claim 1, wherein the coated article is an insulating glass (IG) window unit.

7. The coated article of claim 1, wherein the coated article is an insulating glass (IG) window unit, the IG window unit comprising said glass substrate and another glass substrate spaced therefrom, and wherein the IG window unit has a U-value of no greater than 1.25 W/(m2K).

8. The coated article of claim 7, wherein the IG window unit has a U-value of no greater than 1.15 W/(m2K).

9. The coated article of claim 8, wherein the IG window unit has a U-value of no greater than 1.1 W/(m2K).

10. The coated article of claim 8, wherein the IG window unit has a visible transmission of at least 70%.

11. A method of making a coated article, the method comprising:
providing a glass substrate;

forming a layer comprising silicon nitride or tin oxide on the glass substrate;
sputtering a ceramic target comprising zinc and oxygen in an atmosphere including at least an inert gas in order to form a layer comprising zinc oxide on the glass substrate over and directly contacting the layer comprising silicon nitride or tin oxide;

forming a layer comprising an oxide of Ni and/or Cr on the glass substrate over and directly contacting the layer comprising zinc oxide;

forming an infrared (IR) reflecting layer comprising silver on the glass substrate over and directly contacting the layer comprising an oxide of Ni and/or Cr;
and forming a dielectric layer over at least the IR reflecting layer, wherein the coated article has a visible transmission of at least 80%, wherein the coating has a sheet resistance of no greater than 3.8 ohms/square, and wherein there is only one IR reflecting layer comprising silver in the coating.

12. The method of claim 11, further comprising sputter-depositing a layer comprising an oxide of titanium on the glass substrate so as to be located between at least the substrate and the layer comprising silicon nitride or tin oxide.

13. The method of claim 11, wherein the layer comprising silicon nitride or tin oxide, comprises silicon nitride.

14. The method of claim 11, further comprising thermally tempering the coated article

15. The coated article of claim 1, wherein the coated article has a .DELTA.E*
value of no greater than 4.0 due to heat treatment of at least one of: transmissive;
and a film side reflective.

16. The coated article of claim 1, wherein the coated article has a .DELTA.E*
value of no greater than 3.0 due to heat treatment of at least one of: transmissive;
and a film side reflective.