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 .
Specification
The objection to the title is withdrawn in view of applicants’ submission of a replacement title.
Claim Objections
The objection to claim 1 is withdrawn in view of applicants’ claim amendments.
Terminal Disclaimer
The terminal disclaimer filed on July 15, 2026, disclaiming the terminal portion of any patent granted on this application which would extend beyond the expiration date of U.S. Patent Appl. Publ. No. 18/92,926, No. 18/695,073, and No. 18/867,900 has been reviewed and is accepted. The terminal disclaimer has been recorded.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(B) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 8, 14, and 20-22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 8 recites the limitation "the reduced-pressure CVD apparatus" in ll. 6-7. There is insufficient antecedent basis for this limitation in the claim. It is assumed applicants intended to recite “a reduced-pressure CVD apparatus” in ll. 6-7 and then “the reduced-pressure CVD apparatus” in ll. 9-10.” Dependent claims 14 and 20-22 are similarly rejected due to their dependence on claim 8.
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.
Claims 8, 14, and 20-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over a publication to Komiyama, et al. entitled “Schottky diode characteristics of 3C-SiC grown on a Si substrate by vapor phase epitaxy,” Journal of Crystal Growth, Vol. 275, pp. c1001-06 (2005) (hereinafter “Komiyama”) in view of U.S. Patent Appl. Publ. No. 2018/0363166 to Wada, et al. (“Wada”) and further in view of Japanese Patent Appl. Publ. No. JP2019-117908A to Uratani, et al. (“Uratani”).
Regarding claim 8, Komiyama teaches a method for producing a heteroepitaxial wafer heteroepitaxially growing a 3C-SiC single crystal film on a single crystal silicon substrate (see the Abstract, Figs. 1-7, and entire reference which teach a method of heteroepitaxially growing a 3C-SiC single crystal on a single crystal Si substrate), the method comprising:
a first step of removing a native oxide film on a surface of the single crystal silicon substrate by hydrogen baking (see the Experimental Procedure section at pp. c1002-03 which teaches performing a thermal cleaning by annealing the Si substrate in purified hydrogen at a temperature of 1,100 °C at a pressure of 10 to 100 Torr which will necessarily remove the native oxide); and
a second step of supplying a source gas containing carbon and silicon into the reduced-pressure CVD apparatus and forming the 3C-SiC single crystal film having wettability with a contact angle of 50° or less with liquid (H2O) on a surface thereof (See the Experimental Procedure section at pp. c1002-03 which teaches supplying methylsilane at a temperature of 700 to 900 °C in order to grow a 3C-SiC buffer layer. See also Figs. 1, 2(b), & 3 and associated descriptive text in the Results and Discussion section at pp. c1003-04 which teach that under optimized conditions a smooth and epitaxial 3C-SiC layer is produced on the Si substrate. Since the method of Komiyama performs each and every step of the disclosed and claimed process using a substantially identical temperature and pressure it must necessarily produce the same results, namely a wettability with a contact angle of 50° or less with liquid H2O on a surface thereof (also see infra with respect to the use of a Si(111) substrate as per the teachings of Uratani). Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See also MPEP 2112.01. Alternatively, 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 wettability with a contact angle of 50° or less with liquid H2O on a surface thereof, if not clearly envisaged, would be reasonably expected by the skilled artisan. See Leinoff v. Louis Milona & Sons, Inc. 220 USPQ 845 (CAFC 1984).),
wherein the first step and the second step are performed using a reduced-pressure CVD apparatus (see the Experimental Procedure section at pp. c1002-03 which teaches the use of a low-pressure CVD system),
a nucleation stage to perform a SiC nucleation on the single crystal silicon substrate and a film-forming stage to form the 3C-SiC single crystal film by growing a SiC single crystal are included as the second step (see the Experimental Procedure section at pp. c1002-03 which teaches supplying methylsilane at a temperature of 700 to 900 °C in order to grow a 3C-SiC buffer layer followed by supplying silane and propane at a temperature of 1,150 °C in order to grown an active 3C-SiC layer), and
the nucleation stage is performed on condition that pressure is 13332 Pa or lower and a temperature is maintained at a constant temperature in a range of 300 °C or higher and 950 °C or lower (see the Experimental Procedure section at pp. c1002-03 which teaches that the 3C-SiC buffer layer is grown by supplying methylsilane at a temperature of 700 to 900 °C and a pressure of 10 to 100 Torr (i.e., 1,333 to 13,332 Pa)), and
the film-forming stage is performed on condition that the pressure is 6666 Pa or lower, and the temperature is 800 °C or higher and 1200 °C or lower (See the Experimental Procedure section at pp. c1002-03 which teaches that the active 3C-SiC layer is grown at a temperature of 1,150 °C while the pressure is maintained at 10 to 100 Torr (i.e., 1,333 to 13,332 Pa) which falls within and, hence, substantially overlaps the claimed ranges. Accordingly, it would have been within the capabilities of a PHOSITA prior to the effective filing date of the invention to utilize a pressure of 6,666 Pa or lower in the method of Komiyama as it is within the disclosed range of 10 to 100 Torr.).
Even if it is assumed arguendo that Komiyama does no teach that the 3C-SiC single crystal film forms a contact angle of 50° or less with liquid H2O on a surface thererof, this would have been obvious in view of the teachings of Wada. In Figs. 2-3 & 22, ¶[0081], ¶¶[0161]-[0163], and claim 13 as well as elsewhere throughout the entire reference Wada teaches an analogous embodiment of an epitaxial SiC layer (28) and a buffer layer (27) deposited onto a substrate (100) by CVD. In ¶[0081] and ¶¶[0161]-[0163] Wada specifically teaches that when pure water is dropped onto the SiC substrate an average value of the contact angle formed is less than or equal to 45° and that a higher hydrophilicity is preferred since, for example, particles on the surface can be more efficiently removed when cleaning the surface of the SiC substrate. Thus, a PHOSITA prior to the effective filing date of the invention would be motivated to produce the 3C-SiC epitaxial layer in the method of Komiyama under conditions that produce a contact angle with pure water that is less than or equal to 45° in order to provide a surface that can be more efficiently cleaned/processed during device fabrication.
Komiyama and Wada do not teach that the single crystal silicon substrate has a plane orientation of (111) or that the film forming stage forms a vacancy directly under the 3C-SiC single crystal film. However, in Fig. 1 and the associated descriptive text in the Description of Embodiments section Uratani teaches that a compound semiconductor substrate (CS1) comprised of 3C-SiC may be produced on a Si(111) substrate (1) by deposition of first (21) and second (22) SiC layers (2) thereupon. In the third paragraph on p. 3 Uratani specifically teaches that the surface plane, such as the (111) plane, that is utilized for film growth is selected based upon the orientation of the GaN crystal to be finally formed. Thus, a PHOSITA prior to the filing date of the invention would be motivated to utilize a Si(111) substrate as the growth surface in the method of Komiyama and Wada in order to produce a GaN crystal upon the deposited 3C-SiC layer which has the desired crystal structure and orientation. Moreover, as already noted supra, since the combination of Komiyama, Wada, and Uratani perform each and every step of the claimed process it must necessarily produce the same results, including the formation of a vacancy directly under the 3C-SiC film as claimed.
Regarding claim 14, Komiyama teaches that the first step is performed on condition that the temperature is 1000 °C or higher and 1200 °C or lower (see the Experimental Procedure section at pp. c1002-03 which teaches performing a thermal cleaning by annealing the Si substrate in purified hydrogen at a temperature of 1,100 °C).
Regarding claim 20, Komiya teaches that the source gas is monomethylsilane or trimethylsilane (see the Experimental Procedure section at pp. c1002-03 which teaches the use of methylsilane to deposit the 3C-SiC buffer layer).
Regarding claim 21, Komiyama and Wada do not teach that a GaN layer is formed on the surface of the formed 3C-SiC single crystal film by further growing GaN thereon. However, as noted supra with respect to the rejection of claim 1, in Fig. 1 and the associated descriptive text in the Description of Embodiments section Uratani teaches that a compound semiconductor substrate (CS1) comprised of 3C-SiC may be produced on a Si(111) substrate (1) by deposition of first (21) and second (22) SiC layers (2) thereupon. In Fig. 9 and the Modification section Uratani further teaches that the compound semiconductor substrate (CS1) may be utilized to produce a second compound semiconductor substrate (CS2) which includes a HEMT by depositing, inter alia, a GaN layer (7) onto the 3C-SiC single crystal film (2). Thus, a PHOSITA prior to the effective filing date of the invention would recognize that the 3C-SiC single crystal film of Komiyama may be used for the growth of epitaxial GaN thereupon and would be motivated to do so to produce HEMT devices on larger and more cost-efficient Si Substrates.
Regarding claim 22, Komiyama teaches that the film-forming stage is performed on condition that the pressure is 1333 Pa or lower (See the Experimental Procedure section at pp. c1002-03 which teaches that the active 3C-SiC layer is grown at a temperature of 1,150 °C while the pressure is maintained at 10 to 100 Torr (i.e., 1,333 to 13,332 Pa) which falls within and, hence, substantially overlaps the claimed ranges. Accordingly, it would have been within the capabilities of a PHOSITA prior to the effective filing date of the invention to utilize a pressure of 1,333 Pa in the method of Komiyama as it touches the lower limit of the disclosed range of 10 to 100 Torr.)
Response to Arguments
Applicants’ arguments filed July 15, 2026, 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 initially argue that since the 3C-SiC film in Komiyama is formed on the Si(001) substrate rather than a Si(111) substrate as claimed, the resulting 3C-SiC film and the H2O contact angle thereupon will differ. See applicants’ 7/15/2026 reply, pp. 7-8. Applicants’ argument is noted, but is moot in view of the introduction of Uratani to teach that the use of a Si(111) substrate for the growth of 3C-SiC is known in the art and a suitable motivation to combine is provided.
Applicants then argue that since Komiyama teaches growth at a pressure range of 10 to 100 Torr (i.e., 1333 to 13,332 Pa), there is no specific disclosure that the pressure is maintained at 6,666 Pa or less as recited in claim 8. Id. at pp. 8-9. Applicants’ argument is noted, but is unpersuasive. In this case there is substantial overlap between the 1333 to 13,332 Pa pressure range in Komiya and the pressure of 6,666 Pa or less as recited in claim 8. This is necessarily the case as a pressure range of 1,333 to 6,666 Pa encompasses (6,666 Pa – 1,333 Pa) / (13,332 Pa – 1,333 Pa) × 100 = 44.4 % of the range disclosed in Komiyama. Accordingly, the Examiner has properly set forth a prima facie case of obviousness based upon overlapping ranges.
Applicants then argue that by setting the pressure and temperature during the film forming stage within an appropriate numerical range as in the present invention, vacancies can be formed directly under the 3C-SiC film and that this provides an advantageous effect. Id. at p. 9. Applicants’ argument is noted, but it is pointed out that the cited prior art of record teaches 3C-SiC growth using temperature and pressure ranges which substantially overlap the ranges as disclosed and claimed in the instant application. Since the method of Komiyama, Wada, and Uratani perform each and every step of the claimed process it must necessarily produce the same results, including the formation of a vacancy directly under the 3C-SiC film as claimed.
Applicants argue that Wada cannot be combined with Komiyama because Wada teaches the growth of a 4H-SiC layer onto a SiC substrate rather than a 3C-SiC layer onto a Si substrate. Id. at pp. 9-10. Applicants’ argument is noted, but is unpersuasive. In at least ¶[0081] Wada teaches that the contact angle of less than 45° is formed on the SiC epitaxial substrate (100) and does not teach or suggest that different SiC polytypes produce a significant difference in the contact angle or that there is a difference in the surface of SiC when it is measured as a film as opposed to a substrate. In both cases the surface is comprised of the same material, namely that of SiC. In ¶¶[0161]-[0163] Wada further teaches that a small contact angle of equal to or less than 45° is desirable as this facilitates more efficient removal of small particles from the surface. So even if the method of Komiyama allegedly does not produce a contact angle of 50° or less a PHOSITA would be motivated to utilize routine experimentation to determine the growth conditions that produce a contact angle of 50° or less as claimed in order to provide a surface which can be cleaned more efficiently prior to performing one or more subsequent film growth processes.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KENNETH A BRATLAND JR whose telephone number is (571)270-1604. The examiner can normally be reached Monday- Friday, 7:30 am to 4:30 pm EST.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714
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