DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Interpretation
It is noted that the use of the term “organometallic chlorine” in claims 1, 9, and 18 would ordinarily be interpreted as a compound comprising chlorine, an organic moiety, and a metal atom. However, at least ¶[0050] and ¶[0057] of the published application disclose the use of chlorine-containing compounds which include an organic moiety or a metal atom, but not both. Thus, for examination purposes “organometallic chlorine” is interpreted as a precursor comprising chlorine and one or more of an organic moiety and a metal atom.
Claim Rejections - 35 USC § 112
The 35 U.S.C. 112(b) rejection of claims 12-13, 18-19, and 21-25 is withdrawn in view of applicants’ claim amendments.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 1-2, 4, 7-8, 11-13, 18-22, 24-26, and 28 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Appl. Publ. No. 2015/0364319 to Park, et al. (hereinafter “Park”) in view of U.S. Patent Appl. Publ. No. 2005/0132950 to Kim, et al. (hereinafter “Kim”).
Regarding claim 1, Park teaches a method (see, e.g., the Abstract, Figs. 1-9, and entire reference) comprising:
exposing a gallium nitride (GaN) layer or surface to a chlorine (Cl) precursor and NH3 within a reactor under conditions sufficient to etch the layer or surface, thereby etching the GaN layer or surface (see, e.g., Figs. 3A-B, ¶[0071], and ¶¶[0076]-[0084] which teach exposing a GaN layer (135) to an etching gas which includes chlorine (Cl2) and ammonia (NH3) within a reactor in order to etch the GaN layer (135));
wherein the etching comprises a net removal of GaN from the layer or surface (see, e.g., Figs. 3A-B, ¶[0071], and ¶¶[0076]-[0084] which teach that the etching produces etching holes (140) and, consequently, a net removal of GaN from the surface).
Park does not teach that the chlorine precursor is an organometallic chlorine precursor. However, in Figs. 2-3 and ¶¶[0023]-[0035] and the Example in ¶¶[0036]-[0042] Kim teaches a method of forming a GaN seed layer (33) on a substrate (31) in step (S23) and then growing an AlGaN epitaxial layer (37”) and (37) using ammonia (NH3) as a nitrogen source while simultaneously etching the GaN layer (33) with a Cl-containing precursor gas in step (S27). In ¶[0032] and claim 5 Kim specifically teaches that the Cl-containing etching gas may be comprised of an organometallic chlorine gas such as CCl4. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Kim and would recognize that an organometallic chlorine precursor such as CCl4 may be utilized in place of Cl2 as the etchant in the method of Park as this would involve nothing more than the use of a known equivalent for the same purpose. It is prima facie obvious to combine or substitute known equivalents for the same purpose. See MPEP 2144.06. Moreover, the simple substitution of one known element for another to obtain predictable results is within the capabilities of a person of ordinary skill in the art. See, e.g., MPEP 2143(B).
Park and Kim do not explicitly teach that the net removal comprises a layer-by-layer removal. However, since a GaN etching process which utilizes chlorine occurs by sequentially removing layers of Ga and N atoms (as opposed to chunks or particles), it may be considered as occurring on a layer-by-layer fashion. Moreover, since the method of Park and Kim performs each and every step of the claimed process it must necessarily produce the same results, namely that of etching in a layer-by-layer process. It is axiomatic that one who performs the steps of the known process must necessarily produce all of its advantages. Mere recitation of a newly discovered function or property, that is inherently possessed by things in the prior art does not cause a claim drawn to these things to distinguish over the prior art. Therefore, a net removal in a layer-by-layer fashion, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).
Regarding claim 2, Park teaches that the exposing occurs at a temperature below 950 °C (see ¶[0079] which teaches that the GaN layer (135) may be etched at a temperature of 850 °C or more which overlaps the claimed range).
Regarding claim 4, Park teaches increasing or decreasing the GaN etching rate by increasing or decreasing a flow rate of the NH3 within the reactor (see ¶[0081] which teaches that the etching rate may be adjusted according to the ratio of the chlorine gas to the ammonia gas; accordingly, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to increase or decrease the flow rate of ammonia relative to the chlorine gas in order to increase or decrease the GaN etching rate to the desired value).
Regarding claim 7, Park teaches regrowing GaN on the etched GaN layer or surface after the exposing by organometallic vapor phase epitaxy (OMVPE) (see Figs. 4A-B and ¶¶[0085]-[0092] which teach the growth of a GaN layer (160) by metalorganic chemical vapor deposition), but does not teach that growth is performed in the presence of the organometallic Cl precursor. However, in Figs. 2-3 and ¶¶[0023]-[0035] and the Example in ¶¶[0036]-[0042] Kim teaches the growth of a GaN-containing layer (e.g., AlGaN (37”) and (37)) on a GaN seed layer (33) by MOCVD in the presence of a Cl-containing organometallic precursor such as CCl4. The inclusion of the Cl-containing precursor facilitates etching of polycrystals which form on the underlying dielectric mask and thereby produces a higher quality GaN layer. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to include an organometallic Cl precursor such as CCl4 during growth of the GaN layer (160) in the method of Park in order to minimize the formation of polycrystalline GaN on the mask layer (150).
Regarding claim 8, Park and Kim do not explicitly teach that the regrowth is performed without exposing the etched GaN layer or surface to atmosphere. However, since exposing the etched GaN layer (135) to the atmosphere necessarily causes it to be exposed to potential atmospheric contaminants such as oxygen and the like, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to perform growth of the GaN layer (160) in Figs. 4A-B of Park onto the etched GaN layer (135) without exposing the etched surface to the atmosphere in order to minimize the propensity for contaminants to be present at the film-substrate interface after etching and before performing any subsequent film growth processes.
Regarding claim 11, Park teaches controlling organometallic Cl precursor levels within the reactor, thereby controlling a speed of the GaN surface or layer etching (see ¶[0081] which teaches that the etching rate may be adjusted according to the ratio of the chlorine gas to the ammonia gas; accordingly, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to increase or decrease the flow rate of the organometallic Cl precursor as taught by Kim relative to the ammonia gas in order to adjust the GaN etching rate to the desired value).
Regarding claim 12, Park teaches masking a portion of the GaN layer or surface (see Fig. 4A-B and ¶¶[0085]-[0092] which teach forming a mask pattern (150) on a surface of the GaN layer (135)), but does not teach selectively etching an unmasked portion of GaN layer or surface by the organometallic Cl precursor. However, in Figs. 2-3 and ¶¶[0023]-[0035] and the Example in ¶¶[0036]-[0042] Kim teaches the growth of a GaN-containing layer (e.g., AlGaN (37”) and (37)) on a GaN seed layer (33) by MOCVD in the presence of a Cl-containing organometallic precursor such as CCl4. The inclusion of the Cl-containing precursor facilitates etching of polycrystals which form on the underlying dielectric mask and thereby produces a higher quality GaN layer. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to include an organometallic Cl precursor such as CCl4 during growth of the GaN layer (160) in the method of Park in order to minimize the formation of polycrystalline GaN on the mask layer (150).
Regarding claim 13, Park teaches that the masking is done with a dielectric mask (see, e.g., Fig. 4A and ¶¶[0086]-[0088] which teach that the mask (150) may be comprised of silicon dioxide).
Regarding claim 18, Park teaches a method of growing gallium nitride (GaN) (see, e.g., the Abstract, Figs. 1-9, and entire reference), the method comprising:
inputting a set of reactants into an organometallic vapor phase epitaxy (OMVPE) reactor to deposit GaN by organometallic vapor phase epitaxy (see, e.g., Fig. 4B and ¶[0089] which teaches the growth of a GaN layer (160) by MOCVD which would necessarily occur in a reactor);
wherein the method is preceded or followed by the etching of claim 1 (see Figs. 3-4 and ¶¶[0085]-[0092] which teach that growth of the GaN layer (160) is performed after the underlying GaN layer (135) has been etched).
Park does not teach that the reactants comprise at least trimethylgalltum (TMGa) and ammonia (NH3), inputting an organometallic chlorine (Cl) precursor into the OMVPE reactor, and reacting the organometallic Cl precursor with the TMGa and with the NH3 to deposit GaN. However, in Figs. 2-3 and ¶¶[0023]-[0035] and the Example in ¶¶[0036]-[0042] Kim teaches flowing trimethylgallium, ammonia, and a Cl-containing precursor into a MOCVD reactor in step (S27) in order to deposit a GaN layer by MOCVD with ¶[0032] and claim 5 specifically teaching that the Cl-containing precursor gas may be comprised of an organometallic chlorine gas such as CCl4. The inclusion of the Cl-containing precursor facilitates etching of polycrystals which form on the underlying dielectric mask and thereby produces a higher quality GaN layer. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize TMGa and ammonia with an organometallic Cl precursor such as CCl4 to grow the GaN layer (160) in the method of Park in order to minimize the formation of polycrystalline GaN on the mask layer (150). Moreover, the use of TMGa and ammonia for the deposition of GaN would involve nothing more than the use of known precursors according to their intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07.
Park and Kim do not explicitly teach increasing the growth rate of GaN with the introduction of the Cl precursor. However, since the method of Kim performs each and every step of the claimed process it must necessarily produce the same results, namely that of increasing the growth rate of GaN. It is axiomatic that one who performs the steps of the known process must necessarily produce all of its advantages. Mere recitation of a newly discovered function or property, that is inherently possessed by things in the prior art does not cause a claim drawn to these things to distinguish over the prior art. Therefore, an increase in the growth rate during GaN deposition, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).
Regarding claim 21, Park and Kim do not explicitly teach decreasing the gas phase reaction of TMGa with NH3 based on the inputted organometallic Cl precursor. However, since the method of Park and Kim performs each and every step of the claimed process it must necessarily produce the same results, namely that of increasing the growth rate of GaN. It is axiomatic that one who performs the steps of the known process must necessarily produce all of its advantages. Mere recitation of a newly discovered function or property, that is inherently possessed by things in the prior art does not cause a claim drawn to these things to distinguish over the prior art. Therefore, a decrease in the gas phase reaction of TMGa with NH3 based on the inputted Cl precursor, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).
Regarding claim 22, Park and Kim do not explicitly teach that the gas phase reaction produces solid particles that decrease the growth efficiency. However, since the method of Park and Kim performs each and every step of the claimed process it must necessarily produce the same results, namely that of producing solid particles that decrease the growth efficiency. It is axiomatic that one who performs the steps of the known process must necessarily produce all of its advantages. Mere recitation of a newly discovered function or property, that is inherently possessed by things in the prior art does not cause a claim drawn to these things to distinguish over the prior art. Therefore, a gas phase reaction which produces solid particles that decrease the growth efficiency, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).
Regarding claim 24, Park teaches that the reacting step is performed at a temperature between 700 degrees Celsius to 1,100 degrees Celsius (see ¶[0079] which teaches that the GaN layer (135) may be etched at a temperature of 850 °C or more which substantially overlaps the claimed range).
Regarding claim 25, Park and Kim teach that the inputted set of reactants does not include hydrochloric acid (HCI) (see, e.g., ¶[0079] of Park which teaches the use of Cl2 gas as an etchant ¶[0032] and claim 5 of Kim which teach that the Cl-containing precursor gas may be comprised of an organometallic chlorine gas such as CCl4 which does not include HCl).
Regarding claim 26, Park teaches a method (see, e.g., the Abstract, Figs. 1-9, and entire reference), comprising:
inputting a set of reactants into an organometallic vapor phase epitaxy (OMVPE) reactor to deposit gallium nitride (GaN) onto a surface or layer in the OMVPE reactor (see, e.g., Fig. 4B and ¶[0089] which teaches the growth of a GaN layer (160) onto the surface of the underlying GaN layer (135) by MOCVD which would necessarily occur in a reactor);
wherein the method is preceded or followed by the etching of claim 1 (see Figs. 3-4 and ¶¶[0085]-[0092] which teach that growth of the GaN layer (160) is performed after the underlying GaN layer (135) has been etched).
Park does not teach that the reactants comprise at least trimethylgalltum (TMGa), inputting a chlorine (Cl) precursor into the OMVPE reactor, and depositing GaN with a growth rate based at least in part on the inputted Cl precursor. However, in Figs. 2-3 and ¶¶[0023]-[0035] and the Example in ¶¶[0036]-[0042] Kim teaches flowing trimethylgallium, ammonia, and a Cl-containing precursor into a MOCVD reactor in step (S27) in order to deposit a GaN layer by MOCVD with ¶[0032] and claim 5 specifically teaching that the Cl-containing precursor gas may be comprised of an organometallic chlorine gas such as CCl4. The inclusion of the Cl-containing precursor facilitates etching of polycrystals which form on the underlying dielectric mask and thereby produces a higher quality GaN layer. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize TMGa and ammonia with an organometallic Cl precursor such as CCl4 to grow the GaN layer (160) in the method of Park at a predetermined growth rate in order to minimize the formation of polycrystalline GaN on the mask layer (150). Moreover, the use of TMGa for the deposition of GaN would involve nothing more than the use of a known precursor according to its intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07.
Regarding claim 28, Park and Kim do not explicitly teach increasing the growth rate of GaN with the introduction of the organometallic Cl precursor. However, since the method of Kim performs each and every step of the claimed process it must necessarily produce the same results, namely that of increasing the growth rate of GaN. It is axiomatic that one who performs the steps of the known process must necessarily produce all of its advantages. Mere recitation of a newly discovered function or property, that is inherently possessed by things in the prior art does not cause a claim drawn to these things to distinguish over the prior art. Therefore, an increase in the growth rate during GaN deposition, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).
Claims 5-6, 9, and 23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Park in view of Kim and further in view of a publication to Wolfram, et al. entitled “MOVPE-based in situ etching of In(GaAs)P/InP using tertiarybutylchloride,” Journal of Crystal Growth, Vol. 221, pp. 177-82 (2000) (“Wolfram”).
Regarding claim 5, Park and Kim do not explicitly teach reducing the NH3 levels below the normal level of 25 mbar partial pressure or more used for organometallic vapor phase epitaxy (OMVPE) growth of GaN. However, in ¶[0040] of the Example Kim teaches that the total pressure in the reaction chamber was 200 mbar during deposition of the GaN-containing thin film. Then in the Abstract, Figs. 1-7, the Experimental procedure and Results and discussion sections at pp. 178-80 Wolfram teaches that tetriarybutylchloride (TBC or TBCl) is a known etchant that has been successfully been used to etch Group III-V compound semiconductors such as InP and InGaAsP and produce excellent surface morphology. Moreover, Figs. 1 & 3-6 show that the etching rate is strongly dependent on variable such as the temperature, TBCl partial pressure, the total pressure, and the concentration ratio of TBCl. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would readily recognize that TBCl may be utilized as the Cl-based etching gas in the method of Park and Kim since this would involve nothing more than the use of a known material based on its suitability for its intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07.
Then in Fig. 1 and the corresponding descriptive text at p. 178 Wolfram teaches that the TBCl etching rate increases rapidly as the pressure is reduced to 50 mbar while Fig. 5 shows that the presence of PH3 while etching InP with TBCl produces more than an order of magnitude increase in the etching rate at a total pressure of 50 mbar when the PH3/TBCl ratio is reduced below approximately 200. In this regard, the partial pressure of PH3 when etching InP is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would utilize routine experimentation to determine the amount the NH3 partial pressure may be reduced from conventional MOCVD growth pressures during growth of Group III-nitride epitaxial layers using TBCl as the Cl precursor in the method of Park and Kim with the motivation for doing so being to maximize the etching rate while simultaneously producing a smooth growth surface suitable for the formation of electronic devices thereupon.
Regarding claim 6, Park and Kim do not explicitly teach reducing NH3 levels below the normal level of 25 mbar partial pressure or more used for organometallic vapor phase epitaxy (OMVPE) growth of GaN, in order to reduce the surface roughness during etching. However, in ¶[0040] of the Example Kim teaches that the total pressure in the reaction chamber was 200 mbar during deposition of the GaN-containing thin film. Then in the Abstract, Figs. 1-7, the Experimental procedure and Results and discussion sections at pp. 178-80 Wolfram teaches that tetriarybutylchloride (TBC or TBCl) is a known etchant that has been successfully been used to etch Group III-V compound semiconductors such as InP and InGaAsP and produce excellent surface morphology. Moreover, Figs. 1 & 3-6 show that the etching rate is strongly dependent on variable such as the temperature, TBCl partial pressure, the total pressure, and the concentration ratio of TBCl. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would readily recognize that TBCl may be utilized as the Cl-based etching gas in the method of Park and Kim since this would involve nothing more than the use of a known material based on its suitability for its intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07.
Then in Fig. 1 and the corresponding descriptive text at p. 178 Wolfram teaches that the TBCl etching rate increases rapidly as the pressure is reduced to 50 mbar while Fig. 5 shows that the presence of PH3 while etching InP with TBCl produces more than an order of magnitude increase in the etching rate at a total pressure of 50 mbar when the PH3/TBCl ratio is reduced below approximately 200. In this regard, the partial pressure of PH3 when etching InP is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would utilize routine experimentation to determine the amount the NH3 partial pressure may be reduced from conventional MOCVD growth pressures during growth of Group III-nitride epitaxial layers using TBCl as the Cl precursor in the method of Park and Kim with the motivation for doing so being to maximize the etching rate while simultaneously producing a smooth growth surface suitable for the formation of electronic devices thereupon.
Regarding claim 9, Park and Kim do not explicitly teach that the organometallic Cl precursor comprises tertiarybutylchloride (TBCI). However, in the Abstract, Figs. 1-7, the Experimental procedure and Results and discussion sections at pp. 178-80 Wolfram teaches that tetriarybutylchloride (TBC or TBCl) is a known etchant that has been successfully been used to etch Group III-V compound semiconductors such as InP and InGaAsP and produce excellent surface morphology. Moreover, Figs. 1 & 3-6 show that the etching rate is strongly dependent on variable such as the temperature, TBCl partial pressure, the total pressure, and the concentration ratio of TBCl. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would readily recognize that TBCl may be utilized as the Cl-based etching gas in the method of Park and Kim since this would involve nothing more than the use of a known material based on its suitability for its intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07. Moreover, it is prima facie obvious to combine or substitute known equivalents for the same purpose. See MPEP 2144.06.
Regarding claim 23, Park and Kim do not explicitly teach that the organometallic Cl precursor comprises tertiarybutylchloride (TBCl). However, in the Abstract, Figs. 1-7, the Experimental procedure and Results and discussion sections at pp. 178-80 Wolfram teaches that tetriarybutylchloride (TBC or TBCl) is a known etchant that has been successfully been used to etch Group III-V compound semiconductors such as InP and InGaAsP and produce excellent surface morphology. Moreover, Figs. 1 & 3-6 show that the etching rate is strongly dependent on variable such as the temperature, TBCl partial pressure, the total pressure, and the concentration ratio of TBCl. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Wolfram and would readily recognize that TBCl may be utilized as the Cl-based etching gas in the method of Kim since this would involve nothing more than the use of a known material based on its suitability for its intended use. Use of a known material based on its suitability for its intended use has been held to support a prima facie determination of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1947). See also MPEP 2144.07. Moreover, it is prima facie obvious to combine or substitute known equivalents for the same purpose. See MPEP 2144.06.
Response to Arguments
Applicants’ arguments filed November 3, 2025, have been fully considered, but they are not persuasive and are moot in view of the new grounds of rejection set forth in this Office Action.
Applicants argue that the formation of etching holes in the method of Park is separate and distinct from a layer-by-layer removal and, as such, Park does not teach layer-by-layer removal of GaN as recited in claim 1. See applicants’ 11/3/2025 reply, p. 2. Applicants’ argument is noted, but is unpersuasive. Although the etching process in Figs. 3A-B and ¶¶[0076]-[0084] of Park produces holes (140) due to the occurrence of preferential etching at sites where dislocations are present, this does not mean that layer-by-layer etching of the surface of the sacrificial layer or within the holes (140) themselves does not occur. Since the sacrificial layer (135) is comprised of crystalline GaN it is necessarily comprised of alternating crystalline layers of Ga and N stacked one on top of the other. Thus, as the surface and holes (140) of the sacrificial layer (135) are etched, these individual layers of Ga and N are necessarily sequentially removed in what may be broadly considered as a layer-by-layer fashion. Accordingly, it is the Examiner’s position that the process of etching the sacrificial layer (135) at the surface and within holes (140) occurs in what may be broadly considered as a layer-by-layer fashion as recited in the context of claim 1.
Applicants then argue that the formation of etching holes in a sacrificial layer as disclosed in Park is different from the selective removal of polycrystals formed on a dielectric mask in Kim and that there would be no reasonable expectation of success in replacing Cl2 with CCl4. Id. at pp. 2-3. This argument is not found persuasive as prior art is relevant for all that it reasonably suggests to a person of ordinary skill in the art. In at least ¶[0016] and ¶[0032] Kim provides a list of known etching gases which includes Cl2, CCl4, and HCl which are considered to be equivalents which are capable of etching a Group III-nitride. Thus, the use of CCl4 in place of Cl2 in the method of Park would involve nothing more than the use of a known equivalent for the same purpose which is prima facie obvious.
Applicants subsequently argue that since the conditions utilized for etching in Kim are distinct, the introduction of an organometallic Cl precursor in the method of Park would not necessarily produce an increase in GaN deposition rate. Id. at pp. 3-4. This argument is not found persuasive. As an initial matter it is pointed out that the specific conditions or steps required to increase the growth rate as a result of introducing the organometallic Cl precursor are not recited in amended claim 18 which merely recites “increasing the growth rate of GaN with the introduction of the organometallic Cl precursor.” This limitation is equivalent to a whereby clause which merely recites the intended result of a process step that is positively recited. Since the method taught by the combination of Park and Kim involves introducing an organometallic precursor in the form of CCl4 during GaN growth by MOVPE in the manner recited in the context of claim 18 it therefore performs each and every step of the claimed process and, as such, must necessarily produce the same results which is an increase in the growth rate of GaN. The Examiner also notes that due to the presence of Cl, the use of a Cl-containing precursor would normally be expected to reduce rather than increase the growth rate since Cl tends to etch the surface. This is evident from claim 1 and at least Fig. 8A of the instant application, the latter of which is reproduced below and shows that increasing the TBCl flow rate and temperature leads to a corresponding increase in the etch rate. In Fig. 15
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and ¶[0089] of the published application it appears that adding TBCl under certain conditions during MOVPE of GaN yields an increase in the growth rate as highlighted by arrow (1520). However, there is no indication that this increase would also occur for organometallic Cl precursors other than TBCl and may be solely due to the unique chemistry of TBCl and the particular growth conditions used. If this is the case, then it appears that the full scope of claim 18 may not be fully enabled by the specification as originally filed since there is no indication that organometallic Cl precursor other than TBCl would also produce an increase in the growth rate of GaN during MOVPE growth.
Finally, applicants argue against the rejection of claim 9 by contending that since Wolfram discloses the use of TBCl to etch InP and InGaAsP layers in a MOVPE reactor an ordinary artisan would not utilize TBCl as a selective etchant for polycrystals formed between Al and a dielectric mask in the method of Kim. Id. at pp. 4-5. This argument is not found persuasive for the same reasons mentioned supra with respect to the reliance on Kim. The problem to be solved in the method of Park is not specific to the etching of polycrystals formed on a dielectric mask, but instead it generally relates to the use of a suitable halogen-containing precursor that is capable of etching a Group III-nitride in order to produce the holes (140) in Figs. 3A-B. The teachings of Wolfram show that TBCl is a known Cl-containing etchant that has been successfully utilized to etch Group III-V semiconductor materials. Since Group III-nitrides are Group III-V compounds, a person of ordinary skill in the art would look to the teachings of Wolfram and would readily recognize the potential of TBCl for use as an etchant for Group III-nitrides. In this case, the use of TBCl in place of Cl2 would again involve nothing more than the substitute of a known equivalent for the same purpose which his prima facie obvious.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714