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 .
Election/Restrictions
Applicant’s election of claims 11-15 in the reply filed on 02/16/2026 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.03(a)).
Claims 1-10 and 16-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claims. Claims 11-15 are currently examined on the merits.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference character “700” and “710” has been used to designate different portions in fig 7; reference character “700” and “710” has been used to designate different portions in fig 8; reference character “900” “910” and “920” has been used to designate different portions in figs 9, 10 and 11; reference character “900” “910” “920” “1100” and “1200” has been used to designate different portions in figs 9, 10, 11 and 12; reference character “900” “910” “920” “1100” “1200” “1300” and “1310” has been used to designate different portions in figs 9-13; reference character “900” “910” “920” “1100” “1200” “1410” and “1420” has been used to designate different portions in figs 9-15; reference character “1600” and “1650” has been used to designate different portions in fig 16; reference character “1600” “1650” “1700” and “1720” has been used to designate different portions in figs 17 and 18; reference character “1410” has been used to designate different portions in figs 19-22; reference character “3200” and “3210” has been used to designate different portions in figs 31; reference character “3200” and “3300” has been used to designate different portions in fig 32; reference character “3400” and “3410” has been used to designate different portions in figs 33-34; reference character “3400” and “3600” has been used to designate different portions in fig 35; reference character “3400” “3600” and “3710” has been used to designate different portions in figs 36-38. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference characters "700" and "710" have both been used to designate same portion in fig 7; reference characters "700" and "800" have both been used to designate same portion in fig 8; reference characters "900" “910” and "920" have both been used to designate same portion in figs 9-11; reference characters "900" “910” "920" “1100” and “1200” have both been used to designate same portion in fig 12; reference characters "900" “910” "920" “1100” “1200” “1300” and “1310” have both been used to designate same portion in fig 13; reference characters "900" “910” "920" “1100” “1200” “1400” “1410” and “1420” have both been used to designate same portion in figs 14 and 15; reference characters “1600” and “1650” have both been used to designate same portion in figs 16 and 18; reference characters “1600” “1650” “1700” and “1720” have both been used to designate same portion in fig 17; reference characters “1100” and “1410” have both been used to designate same portion in fig 19-24; reference characters "2310" and "2510" have both been used to designate same portion in figs 24-27; characters "2985" and "2990" have both been used to designate same portion in fig 29; characters "3210" and "3200" have both been used to designate same portion in figs 31-32; characters "3200" and "3300" have both been used to designate same portion in fig 32; characters "3400" and "3410" have both been used to designate same portion in figs 33-34; characters "3400" and "3600" have both been used to designate same portion in fig 35; characters "3400" "3600" and “3710” have both been used to designate same portion in figs 36-38. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the “combined top surface area of each pillar of the plurality of pillars,” “combined area of the surface of the merged epitaxial lateral overgrowth” and “two or more devices in or on the second SiC epitaxial layer” must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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 11-15 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.
The term “low” in claim 11 is a relative term which renders the claim indefinite. The term “low” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
Claim 11 recites the limitation "the sidewalls". There is insufficient antecedent basis for this limitation in the claim.
The recited in claim 11 “…defect propagation from the SiC substrate is reduced by decreasing a ratio of a combined top surface area of each pillar of the plurality of pillars to a combined area of the surface of the merged epitaxial lateral overgrowth…” constitutes an indefinite subject matter. It is not clear what a comparative ratio is being used as a reference point for decreasing the ratio of a combined top surface area of each pillar of the plurality of pillars to a combined area of the surface of the merged epitaxial lateral overgrowth; it is not clear what “combined top surface area of each pillar of the plurality of pillars” and “combined area of the surface of the merged epitaxial lateral overgrowth” means; it is not clear whether the combined top surface area and the combined area of the surface of the merged epitaxial lateral overgrowth refers to one of the plurality of the pillars or all of the plurality pillars. Therefore, the metes and bounds of claim 11 are not readily ascertainable. Clarification and/or correction are/is required. Claims 12-15 are rejected because they depend on claim 11.
The recited in claim 13 “…growing the top surface area of each pillar of the plurality of pillars until a step flow growth has stopped…” constitutes an indefinite subject matter. It is not clear “growing the top surface area of each pillar of the plurality of pillars until a step flow growth has stopped” means, for example, it is not clear how to determine/judge the step flow growth has stopped. Therefore, the metes and bounds of claim 13 are not readily ascertainable. Clarification and/or correction are/is required.
The term “substantially” in claim 13 is a relative term which renders the claim indefinite. The term “substantially” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
The recited in claim 14 “…the plurality of pillars are configured to be oriented in the <1120> or <1100> directions…” constitutes an indefinite subject matter. It is not clear which portion/surface of the plurality of pillars are configured to be oriented in the <1120> or <1100> directions. There is also insufficient antecedent basis for limitation "the <1120> or <1100>" in the claim. Therefore, the metes and bounds of claim 14 are not readily ascertainable. Clarification and/or correction are/is required.
Claim 15 recites the limitation "the on-axis surface" and “the <0001> direction”. There is insufficient antecedent basis for this limitation in the claim.
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 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 of this title, 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 11 and 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over Ravi et al (US 20220189761 A1, “Ravi”), or, in the alternative, under 35 U.S.C. 103 as being unpatentable over Ravi et al (US 20220189761 A1, “Ravi”) in view of Zuo et al (CN 111584351 A, machine translation, “Zuo”).
Regarding claim 11, Ravi teaches a method for growing one or more low defect Silicon Carbide (SiC) epitaxial layers comprising providing a SiC wafer 12 (substrate) (figs 1-4, abstract, 0036, 0037); forming a plurality of openings/trenches (e.g., pillars/strips formed between the openings/trenches) in the SiC substrate (wafer) (figs 1-4, abstract, 0011, 0014, 0015, 0036, 0038-0042, claims 1 and 7-9); and growing a buffer SiC epitaxial layer/single crystal layer 24 (first SiC epitaxial layer) using epitaxial lateral overgrowth wherein the epitaxial lateral overgrowth includes epitaxial lateral overgrowth from the sidewalls of each pillar (formed between the openings/trenches) of the plurality of pillars (formed between the openings/trenches) and wherein a surface of the first SiC epitaxial layer comprises a top surface area of each pillar (formed between the openings/trenches) of the plurality of pillars (formed between the openings/trenches) and a surface of a merged epitaxial lateral overgrowth (MELO) between pillars of the plurality of pillars (between trenches) (figs 1-4, abstract 0011, 0015, 0016, 0042-0045, claims 1, 9 and 10); growing another epitaxial layer/device epitaxial SiC layer 28 (second SiC epitaxial layer) overlying the first SiC epitaxial layer being defect free (figs 1-4, abstract, 0011, 0035, 0043-0048, claim 1), reading on defect propagation from the SiC substrate being reduced, but does not explicitly teach the defect propagation from the SiC substrate being reduced by decreasing a ratio of a combined top surface area of each pillar of the plurality of pillars to a combined area of the surface of the merged epitaxial lateral overgrowth. However, Ravi teaches “defect propagation from the SiC substrate being reduced” as adjust addressed, and “defect propagation from the SiC substrate being reduced” by decreasing a ratio of a combined top surface area of each pillar of the plurality of pillars to a combined area of the surface of the merged epitaxial lateral overgrowth” is a product by process limitation. Where the claimed and prior art products are identical or substantially identical in structure or composition, a prima facie case of either anticipation or obviousness has been established, consult In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). It is then Applicants' burden to prove that an unobvious difference exists, see In re Marosi, 218 USPQ 289,292-293 (CAFC 1983). Furthermore, Zuo teaches a method of growing epitaxial layers, wherein defects/dislocations propagation/ penetrating from a SiC substrate being reduced/ annihilated by increasing a hypotenuse of trenches to from V-shaped pits (abstract, 0009, 0025, 0030, 0035), e.g., a combined top surface of pillars/protrusions formed between the trenches/V-shaped pits being decreased and a ratio of a combined top surface area of each pillar of the plurality of pillars to a combined area of the surface of the merged epitaxial lateral overgrowth apparently being decreased. Therefore, it would have been obvious that one of ordinary skill in the art before the effective filing date of the claimed invention would have modified Ravi per teachings of Zuo in order to produce improved crystal quality/crystal device by significantly reducing dislocations/ defects (Zuo abstract, 0030).
Regarding claim 13, Ravi/Zuo teaches providing the SiC substrate as 4H (Hexagonal) SiC wherein a surface of the SiC substrate is off-axis 4 or 8 degrees (in a range of 2-8 degrees) (Ravi 0037, Zuo 0006); growing the top surface area of each pillar of the plurality of pillars and growing the epitaxial lateral overgrowth as 4H (Hexagonal) SiC epitaxial lateral overgrowth (Ravi figs 2-4; abstract 0011, 0015, 0016, 0042-0045, claims 1, 9 and 10); performing a kiss polish on the first SiC epitaxial layer surface wherein the kiss polish is performed off-axis substantially equal to the off-axis surface of the SiC substrate (Ravi abstract, 0011, 0043); growing the second SiC epitaxial layer using epitaxial vertical growth wherein the SiC substrate, the first SiC epitaxial layer, and the second SiC epitaxial layer are single crystal (figs 2-4, abstract, 0011, 0035, 0043-0048, claim 1); and forming two or more devices in or on the second SiC epitaxial layer (abstract, 0011, 0049, 0050, 0062, 0063). Ravi/Zuo teaches growing the top surface area of each pillar of the plurality of pillars and growing the epitaxial lateral overgrowth as 4H (Hexagonal) SiC epitaxial lateral overgrowth, as just addressed, and further teaches a step flow growth (Zuo 0006), but does not explicitly teach growing the top surface area of each pillar of the plurality of pillars until a step flow growth has stopped. However, it is well established that in general, the transposition of process steps or the splitting of one step into two, where the processes are substantially identical or equivalent in terms of function, manner and result, was held not to patentably distinguish the process (e.g., Exparte Rubin, 128 USPQ 440 (Bd. Pat. App. 1959). See MPEP 2144.04 (IV) (C).
Regarding claim 14, Ravi/Zuo teaches etching a plurality of trenches in the SiC substrate to form the plurality of pillars wherein the plurality of pillars are configured to be oriented in the <1120> or <1100> directions (Ravi abstract, 0011, 0014, 0036, 0038, 0039, claims 1, 5 and 7-9; Zuo abstract, 0007, 0012, 0021, 0041), wherein the top surface area of each is in a range of 2-2.5 micros (0.25 microns to 4.0 microns) (Zuo 0021, 0041, claim 4), wherein a spacing (trench/opening) between each adjacent pillar of the plurality of pillars in a range of 20nm to several microns (0.25 microns to 4.0 microns) (Ravi 0036, 0038 and claim 6; Zuo 0021, 0041 and claim 4), and wherein a height of each pillar of the plurality of pillars in a range of 1-3 microns (0.25 microns to 4.0 microns) (Ravi 0039). Overlapping ranges are prima facie obvious. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976) (MPEP 2144.05 I). It is also well-established that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In reAller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 15, Ravi/Zuo teaches orienting the on-axis surface faceting of the first SiC epitaxial layer in the <0001> direction (Ravi 0036, Zuo 0006). Further, it is well-established that the selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). Also see MPEP 2144.07.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Ravi/Zuo as applied to claim 11 above, and further in view of Kaneko et al (US 20180312992 A1, “Kaneko”).
Regarding claim 12, Ravi/Zuo teaches the first SiC epitaxial layer overlies or is formed in an entire surface of the SiC substrate (figs 1-4, abstract 0011, 0015, 0016, 0042-0045, claims 1, 9 and 10), but does not explicitly teach that the top surface of each pillar of the plurality of pillars having a circular shape, a triangular shape, a square shape, a rectangular shape, a hexagonal shape, or a truncated pyramid shape. However, Kaneko teaches a method, wherein a top surface of each protrusion (pillar) of a plurality of pillars protrusions) have a rectangular or square shape (abstract, 0023, 0055 and claim 6). Therefore, it would have been obvious that one of ordinary skill in the art before the effective filing date of the claimed invention would have modified Ravi/Zuo per teachings of Kaneko in order to enable the epitaxial growth to occur under suitable conditions for produce wafers/device with a higher quality (Kaneko 0024, 0024, 0079).
Conclusion
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/HUA QI/ Primary Examiner, Art Unit 1714