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 Rejections - 35 USC § 103
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 1-2, 4-10, and 12-17 are rejected under 35 U.S.C. 103 as being unpatentable over Kinoshita (US 2022/0199824) in view of Bauer et al. (US 2019/0035884).
Regarding claim 1, Kinoshita discloses a semiconductor power device, comprising:
a semiconductor body (40) including a semiconductor substrate (41) and an epitaxial layer (42) formed on the semiconductor substrate [Fig. 2 and paragraph 0074];
an active area (1) and a termination area (2) adjacent the active area arranged in the epitaxial layer [Fig. 2];
wherein the termination area (2) comprises a plurality of first rings (31) of a first polarity (P++),
wherein the semiconductor substrate (41) and the epitaxial layer (42) have the second polarity (n-type: N+/N-) [Fig. 2];
wherein the epitaxial layer (42) has a dopant concentration (N-) associated with the second polarity (n-type)
wherein the termination area (2) further comprises a junction termination extension (JTE) border (32) of the first polarity type (P--), and wherein the rings are separately formed from and arranged inside the junction termination extension border (32) [Fig. 2].
However, Kinoshita does not disclose a plurality of second rings of a second polarity different from the first polarity.
Bauer teaches:
wherein the termination area (TR) comprises a plurality of first rings (10) of a first polarity (P-type), and a plurality of second rings (15) of a second polarity (n-type) different from the first polarity (p-type) [Fig. 1 and paragraphs 0038];
wherein the epitaxial layer (5) has a dopant concentration (N-) associated with the second polarity (n-type) that is smaller than a dopant concentration (N+) in the second rings (15) associated with the second polarity (n-type) [Fig. 1 and paragraph 0039].
Therefore, one of ordinary skill in the art, before the effective filing date of the claimed invention, would have been motivated to modify Kinoshita by including a plurality of second rings (15) of a second polarity as taught by Bauer because it helps to increase the electric field coupling from floating field ring to floating field ring [paragraph 0011].
Regarding claim 2, Kinoshita wherein the first rings (31) associated with the first polarity (p-type) have a dopant concentration (P++) that is higher than a dopant concentration (P--) of the JTE border (32) associated with the first polarity (p-type) [Fig. 2].
Regarding claim 4, Bauer teaches wherein the dopant concentration in the second rings (15) associated with the second polarity is at least 100 times larger than the dopant concentration in the epitaxial layer (5b) associated with the second polarity (N-type) [paragraphs 0036 and 0039]. The court has held that 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, 541F.2d 257,191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990).
Regarding claim 5, Bauer teaches wherein the first rings (10) and second rings (15) are arranged alternately [Fig. 1].
Regarding claim 6, Bauer teaches wherein the first and second rings (10/15) are configured to be electrically floating during operation [paragraphs 0011, 0035 and 0038].
Regarding claim 7, Kinoshita discloses wherein the termination area (2) is at least partially covered by a passivation layer (19) [Fig. 2]; wherein the passivation layer (19) comprises a passivation layer made of a material selected from the group consisting of Silicon Nitride, Silicon Oxynitride, Silicon Oxide, and Metallic Oxide; and/or wherein the passivation layer comprises a field oxide [paragraphs 0082 and 0106].
Regarding claim 8, Kinoshita discloses wherein the semiconductor power device comprises a device selected from the group consisting of a Merged P-I-N Schottky (MPS) diode, a MOSFET, a JFET, a Schottky barrier, and a PN diode [Fig. 2 and paragraph 0041]. Also. Bauer teaches the same in paragraph 0052.
Regarding claim 9, Kinoshita discloses wherein the semiconductor substrate (41) comprises a Silicon Carbide substrate; and/or wherein the first polarity corresponds to p-type and the second polarity to n-type [Fig. 2 and paragraphs 0041 and 0111].
Regarding claim 10, Kinoshita discloses wherein the dopant concentration of the first rings (31) associated with the first polarity (p-type) lies in a range between 1E19 and 1E20 #/cm3 [paragraph 0063], and wherein the dopant concentration of the JTE border (32) associated with the first polarity lies in a range between 1 E17 and 1 E20 #/cm3 [paragraph 0067]. The court has held that 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, 541F.2d 257,191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990).
Regarding claim 12, Bauer teaches wherein the dopant concentration in the second rings (15) associated with the second polarity (n-type) is at least 100 times larger than the dopant concentration in the epitaxial layer (5b) associated with the second polarity [paragraphs 0036 and 0039]. The court has held that 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, 541F.2d 257,191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990).
Regarding claim 13, Bauer teaches wherein the first rings (10) and second rings (15) are arranged alternately [Fig. 1].
Regarding claim 14, Kinoshita discloses wherein the termination area (2) further comprises a plurality of floating JTE rings (32/30c) of the first polarity (p-type) arranged spaced apart from the first
Regarding claim 15, Kinoshita discloses a channel stopper (33) arranged at or near an edge of the semiconductor power device, wherein the termination area (2) is arranged in between the channel stopper (33) and the active area (1), and wherein the channel stopper (33) is of the second polarity (n-type) [Figs. 1-2].
Regarding claim 16, Kinoshita discloses wherein, when the passivation layer (19) is made of a material selected from the group consisting of Silicon Nitride, Silicon Oxynitride, Silicon Oxide and Metallic Oxide, and extends over the termination area from a region directly above the channel stopper towards the active area, a part of the plurality of first and second rings is covered [Fig. 2 and paragraphs 0082 and 0106].
Regarding claim 17, Kinoshita discloses wherein, when the passivation layer (19) comprises the field oxide, it extends over the termination area (2) from a region directly above the channel stopper (33) towards the active area (1) thereby fully covering the plurality of first .
Allowable Subject Matter
Claims 3, 11 and 18-19 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Wehrhahn-Kilian et al. (US 2019/0165159) teaches a MPS diode (500) in Figure 8.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOSE R DIAZ whose telephone number is (571)272-1727. The examiner can normally be reached Monday-Friday.
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/Jose R Diaz/Primary Examiner, Art Unit 2815