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 .
Response to Amendment
The Amendment filed on 03/31/2026 is acknowledged. Applicant’s amendments to the Claim Rejections under 35 USC § 112 have overcome each and every objections previously set forth in the Non-Final Office Action mailed on 12/31/2025, so rejection is withdrawn. Claim 1 has been amended, and claim 6 has been canceled. Applicant’s amendments to the claims are noted. Claims 1-5 and 7-8 remain pending in the application.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-5 and 7-8 rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for applying a microwave at a power of 1000W to 2400W for a total of 120 seconds to 1200 seconds, does not reasonably provide enablement for applying a microwave of any power and for any duration to increase the resistivity of the silicon carbide wafer, as encompassed by claim 1. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the invention commensurate in scope with these claims.
The specification discloses that the resistivity increase occurs only within specific conditions: too low a power or too short a time fails to improve resistivity, while too high a power or too long a time damages the wafer (Para [0032]). Claim 1 recites "applying a microwave" without any power or duration limitation, thus encompassing conditions the specification shows do not yield the claimed result and requiring undue experimentation to practice the full claimed scope. See MPEP § 2164.08.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Quick (US8617965B1), and further in view of Cichoň (Cichoň, Stanislav et al. “Direct Microwave Annealing of SiC Substrate for Rapid Synthesis of Quality Epitaxial Graphene.” Carbon (New York) 98 (2016): 441–448. Web. (Year: 2015)).
Regarding claim 1, Quick teaches a method of increasing resistivity of a silicon carbide wafer (Table 4, the resistivity of the silicon carbide region is increased from 1.55 Ω·cm to 1.1×10⁵ Ω·cm), comprising:
providing a silicon carbide wafer with a first resistivity (Table 4, a silicon carbide substrate having crystalline defects including carbon vacancies and substitutional nitrogen atoms located in the carbon vacancies, the defective substrate having a resistivity of 1.55 Ω·cm); and
applying a microwave to the silicon carbide wafer (Fig. 14, directing a thermal energy beam onto the silicon carbide material, the thermal energy beam is a laser beam which is being selected from a beam of charged particles, a beam of electrons, a beam of ions, and a beam of electromagnetic radiation),
wherein the silicon carbide wafer after being applied the microwave has a second resistivity higher than the first resistivity (Table 4, the treated silicon carbide region has a resistivity of 1.1×10⁵ Ω·cm, higher than the starting 1.55 Ω·cm; claim 8, a region having a resistivity on the order of 100,000 ohm-cm fabricated from defective silicon carbide having a resistivity on the order of 1.5 ohm-cm),
wherein the silicon carbide wafer has a nitrogen impurity concentration of 1E14 atoms/cm3 to 1E 18 atoms/cm3 (Table 4, n-type 6H-SiC having a nitrogen concentration of 5×10¹⁸ atoms/cm³; the impurity nitrogen effuses from the vacancy sites and lattice to the surface driven by the energy beam, thereby raising resistivity).
But, quick does not explicitly disclose that the applied beam of thermal energy beam is microwave.
However, Cichon teaches applying a microwave to a silicon carbide wafer (page 441, directly applying 2.45 GHz microwave radiation to a SiC substrate to drive a solid-state reaction in the SiC lattice).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to implement the beam of electromagnetic radiation of Quick (US8617965B1) as the microwave radiation of Cichon, since microwave radiation is a known form of electromagnetic radiation applied to silicon carbide substrates, and the selection of a known electromagnetic-radiation source to perform the electromagnetic-radiation irradiation expressly taught by Quick yields the predictable result of irradiating the SiC wafer to effuse nitrogen and increase resistivity. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Regarding claim 2, Quick in view of Cichon teaches the method as claimed in claim 1, but does not explicitly disclose that the microwave has a power of 1000 W to 2400 W. Cichon discloses applying 2.45 GHz microwave radiation to SiC at power on the order of kilowatts (page 441). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to select a microwave power of 1000 W to 2400 W, since microwave power is a result-effective variable controlling the energy delivered to the wafer, and selecting such a power represents an obvious optimization of a known process parameter to obtain a predictable result. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Regarding claim 3, Quick in view of Cichon teaches the method as claimed in claim 1, wherein the step of applying the microwave is performed in a continuous or segmented manner (continuous and segmented/pulsed application are art-recognized modes of operating a microwave source, and selecting either is a choice among a finite number of known operating modes yielding predictable results).
Regarding claim 4, Quick in view of Cichon teaches the method as claimed in claim 1, but does not explicitly disclose that the step of applying the microwave is performed for a total of 120 seconds to 1200 seconds. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to select a total irradiation time of 120 to 1200 seconds, since the total time is a result-effective variable controlling the cumulative energy delivered and the degree of nitrogen effusion taught by Quick, and selecting such a time represents an obvious optimization of a known process parameter. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007).
Claims 5 and 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Quick (US8617965B1) in view of Cichoň (Cichoň, Stanislav et al. “Direct Microwave Annealing of SiC Substrate for Rapid Synthesis of Quality Epitaxial Graphene.” Carbon (New York) 98 (2016): 441–448. Web. (Year: 2015)) as applied to claim 1 above, and further in view of Ellison (US20030079676A1).
Regarding claim 5, Quick in view of Cichoň teaches the method as claimed in claim 1. Quick further teaches that the microwave treatment increases the resistivity of SiC (Quick, Table 4, a first resistivity of 1.55 Ω·cm and a second resistivity of 1.1×10⁵ Ω·cm), demonstrating that SiC resistivity is affected by the treatment and is a result-effective variable.
Ellison also teaches controlling SiC resistivity to obtain semi-insulating substrates. Thus achieving the claimed resistivity ratio would have been a result of routine optimization (Para [0068], high-resistivity SiC crystal having a first resistivity above 10⁵ Ω·cm and a second resistivity in the range of 10⁷ Ω·cm to above 10¹¹ Ω·cm, including values corresponding to the claimed ratio of 1:1.5 to 1:100).
It would have been obvious to one of ordinary skill in the art to obtain such a ratio, wherein the first resistivity and the second resistivity have a ratio of 1:1.5 to 1:100, through routine selection of starting and target resistivities as taught by Ellison.
Regarding claim 7, Quick in view of Cichon teaches the method as claimed in claim 1, but does not disclose wherein the first resistivity is greater than 1E5 Ω·cm.
However, Ellison teaches wherein the first resistivity is greater than 1E5 Ω·cm (Para [0068], silicon carbide crystal having a resistivity verified to be above 10⁵ Ω·cm).
It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the invention, to provide the starting silicon carbide wafer of Quick (US8617965B1) with a first resistivity greater than 1E5 Ω·cm as taught by Ellison (US20030079676A1), in order to begin from a substrate already approaching semi-insulating quality and thereby reach the high-resistivity values desired for high-frequency device substrates (Para [0083]).
Regarding claim 8, Quick in view of Cichon teaches the method as claimed in claim 1, wherein the second resistivity is 1E7 Ω·cm to 1E12 Ω·cm (Quick, Table 4, a second resistivity of 1.1×10⁵ Ω·cm), but does not explicitly disclose a second resistivity of 1E7 Ω·cm to 1E12 Ω·cm.
However, Ellison teaches wherein the resistivity is 1E7 Ω·cm to 1E12 Ω·cm (Para [0068], substrates in the range of 10⁷ Ω·cm to above 10¹¹ Ω·cm).
It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the invention, to drive the second resistivity of the silicon carbide wafer of Quick (US8617965B1) into the 1E7 Ω·cm to 1E12 Ω·cm range as taught by Ellison (US20030079676A1), in order to obtain a semi-insulating substrate suitable for high-frequency device applications (Para [0083]).
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 JAHAE KIM whose telephone number is (571)270-1844. The examiner can normally be reached M-F 9-5.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Fernando Toledo can be reached at (571) 272-1867. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/FERNANDO L TOLEDO/Supervisory Patent Examiner, Art Unit 2897
/JAHAE KIM/Examiner, Art Unit 2897
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