3DETAILED 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/Drawings
The amendment filed 10/14/2025 is objected to under 35 U.S.C. 132(a) because it introduces new matter into the disclosure. 35 U.S.C. 132(a) states that no amendment shall introduce new matter into the disclosure of the invention. The added material which is not supported by the original disclosure is as follows: new sheet 2/4 demonstrates recess shapes that were not previously described with a specificity commensurate with the detail now shown in the drawings; nowhere in the specification are shapes in that cross-sectional view described as now depicted.
Applicant is required to cancel the new matter in the reply to this Office Action.
Drawings
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, on a plane perpendicular to a thickness direction of the N-type silicon carbide substrate, a cross-section shape of each of the first grooves is polygonal, as found in claim 9, must be shown or the feature(s) canceled from the claim(s). No new matter should be entered. The new drawings appear to depict a cross-section shape on plane that is parallel to a thickness direction of the N-type silicon carbide substrate.
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 1-2, 4, and 9 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
(Re Claim 1) It is unclear how to determine if an unintentionally doped silicon carbide layer is present within a device. No standard is readily apparent in the art and the specification is silent about this point. If a process is eventually realized to introduce dopants into a silicon carbide layer, and the same process is then intentionally carried out with this newfound knowledge, isn’t the silicon carbide layer now intentionally doped? Patentability cannot be conferred to an invention when the measure to determine if the invention is practiced in the art shifts according to the peculiar ignorance of each practitioner in the art. See MPEP §2173.05(b). For example, in Brummer, the Board held that a limitation in a claim to a bicycle that recited "said front and rear wheels so spaced as to give a wheelbase that is between 58 percent and 75 percent of the height of the rider that the bicycle was designed for" was indefinite because the relationship of parts was not based on any known standard for sizing a bicycle to a rider, but on a rider of unspecified build. Brummer, 12 USPQ2d at 1655.
During examination, “unintentionally doped silicon carbide layer” was understood to require only that some doping, either from one dopant species or the total doping, for the relevant doped silicon carbide layer is smaller than the doping of some other silicon carbide layer or is explicitly described as an unintentionally doped layer.
Claims 2, 4, and 9 inherit this rejection for indefiniteness.
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 1-2 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Henning et al. (US 2007/0292999), Miura et al. (US 2006/0169987), and Khlebnikov et al. (US 2021/0198804), all of record.
(Re Claim 1) Henning teaches a silicon carbide homoepitaxial substrate, comprising: an N-type silicon carbide substrate (10; Fig. 5A, ¶69); a defect repair layer (16; 16 may be formed on the N-type silicon carbide substrate 10 when the optional layer 12 is not formed; Fig. 5A, ¶70); and an unintentionally doped silicon carbide layer (18; Fig. 3A, ¶70) on the defect repair layer.
Henning has not been shown to teach a silicon carbide homoepitaxial substrate, comprising:
an N-type silicon carbide substrate with first grooves; a defect repair layer on inner walls of the first grooves and outside the first grooves, provided with second grooves corresponding to the first grooves; and an unintentionally doped silicon carbide layer on the defect repair layer, wherein the second grooves are fully filled with the unintentionally doped silicon carbide layer, wherein a conductivity of the unintentionally doped silicon carbide layer is lower than a conductivity of the N-type silicon carbide substrate.
Miura teaches a substrate (1; Fig. 11) with first grooves (4; see the Fig. 11 markup showing the span between each first groove of the substrate) forming a defect repair layer (4; formed from silicon carbide; “It is best suitable to use a SiC layer formed by carbonization, SiC layer formed at lower temperatures…for example, as a material for the buffer layer 4”; ¶54; Fig. 11) on inner walls of the first grooves and outside the first grooves (Fig. 11), provided with second grooves (see the Fig. 11 markup showing the span between each second groove of the defect repair layer) corresponding to the first grooves, wherein the second grooves are fully filled with a silicon carbide layer (5; Fig. 11).
Additionally, Miura teaches that SiC may be used as the material of the substrate (¶67).
A PHOSITA would find it obvious to form the N-type silicon carbide substrate 10 of Henning with first grooves as taught by Miura; such that the defect repair layer 16 of Henning is formed on inner walls of the first grooves and outside the first grooves, and is provided with second grooves corresponding to the first grooves; and the doped silicon carbide layer fully fills the second grooves of the defect repair layer 16, in the manner taught by Miura, in order to improve the film quality of the unintentionally doped silicon carbide layer 18 of modified Henning, by suppressing defect propagation from the substrate into higher silicon carbide layers (“[m]aking the buffer layer more subject to the defect than the SiC layer allows the layer to include the defects. Thus, production of the defects with a higher probability at the specified positions relieves strain. The control of development of the defects causes the defects to disappear, realizing a less-strained and lower defect-density SiC layer.”; ¶48; see also ¶¶62, 67-68).
Khlebnikov teaches concentration ranges for N-type silicon carbide substrates or unintentionally doped silicon carbide (¶80), where the conductivity (the inverse of resistivity) of the unintentionally doped silicon carbide layer is lower than a conductivity of the N-type silicon carbide layers (highest resistivity for N-type silicon carbide of 0.03 ohm-cm; lowest resistivity listed for either an unintentionally doped silicon carbide layer or undoped SiC is 1,500 ohm-cm; ¶80).
As a PHOSITA would find it obvious to form the N-type silicon carbide substrate of modified Henning according to Khlebnikov’s N-type silicon carbide substrate, as that doping treatment predictably produces an N-type silicon carbide substrate as required by an embodiment of Henning. Khlebnikov’s N-type silicon carbide substrate is suitable for power devices (Khlebnikov: ¶80; Henning: ¶44). See Ruiz v. A.B. Chance Co., 357 F.3d 1270, 69 USPQ2d 1686 (Fed. Cir. 2004).
This results in modified Henning having an N-type silicon carbide substrate with a lower bound for conductivity of 1/(0.03 ohm-cm) (Khlebnikov: ¶80).
Furthermore, Khlebnikov teaches that undoped silicon carbide has a conductivity smaller than the N-type silicon carbide (¶80).
As Henning teaches that the unintentionally doped silicon carbide layer may be unintentionally doped and undoped (¶47), a conductivity of the unintentionally doped silicon carbide layer of modified Henning is lower than a conductivity of the N-type silicon carbide substrate as doped according to Khlebnikov, due at least to also being undoped.
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(Re Claim 2) Modified Henning teaches the silicon carbide homoepitaxial substrate of claim 1, wherein the defect repair layer is a P-type silicon carbide layer (¶47).
(Re Claim 9) Modified Henning teaches the silicon carbide homoepitaxial substrate of claim 1, wherein on a plane perpendicular to a thickness direction of the N-type silicon carbide substrate, a cross-section shape of each of the first grooves is polygonal (Miura: Fig. 11-13).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Henning et al. (US 2007/0292999), Miura et al. (US 2006/0169987), and Khlebnikov et al. (US 2021/0198804), all of record, as applied to claim 2 above, and further in view of Majhi et al. (US 2011/0147845), Sriram (US 2003/0075719), and Chirovsky et al. (US 6,169,756), all of record.
(Re Claim 4) Modified Henning teaches the silicon carbide homoepitaxial substrate of claim 2, but has not been shown to explicitly teach the silicon carbide homoepitaxial substrate wherein in a thickness direction of the N-type silicon carbide substrate, doping of P-type ions in the P- type silicon carbide layer comprises at least one of: uniform doping, modulation doping, or Delta doping.
Sriram teaches forming a defect repair layer (14; buffer layer 12 is optionally formed; Fig. 1, ¶29) as a P-type silicon carbide layer (¶¶30, 33) that is delta doped (¶30).
A person having ordinary skill in the art before the effective filing date of the claimed invention would find it obvious to form the P-type silicon carbide layer 16 of modified Henning with a Delta doping in a thickness direction of the N-type silicon carbide substrate, as taught by Sriram, as this is an appropriate dopant profile for a P-type silicon carbide layer situated on an N-type silicon carbide substrate, Delta doping is a well known technique that predictably introduces dopants into a layer (Chirovsky: col. 8 ln. 14-20), and a Delta doped layer may improve short channel characteristics (Majhi: ¶5). See Ruiz v. A.B. Chance Co., 357 F.3d 1270, 69 USPQ2d 1686 (Fed. Cir. 2004).
Response to Arguments
Applicant's arguments filed 10/14/2025 have been fully considered but they are moot in view of the new rejection.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Christopher A Schodde whose telephone number is (571)270-1974. The examiner can normally be reached M-F 1000-1800 EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jessica Manno can be reached at (571)272-2339. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/CHRISTOPHER A. SCHODDE/Examiner, Art Unit 2898
/JESSICA S MANNO/SPE, Art Unit 2898