Detailed Action
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 Species A, directed at the embodiment of Fig. 3A, is acknowledged. However, Claim 10 has not been withdrawn. Claim 10 is directed towards the GaN layer 15 having a pGaN portion 15-1 and an nGaN portion 15-2, which appears in Figs. 8a-8d which are incongruous with the embodiment of Fig. 3A. Therefore, claims 10-12 are considered withdrawn.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 2, 7, 9 and 14-16are rejected under 35 U.S.C. 102(a)(2) as being anticipated by U.S. Pat. Pub. No. 20210336045 to Oh et al. (Oh).
Regarding Claims 1, 2, 14 and 16, Oh teaches in Fig. 2 at least, a field effect transistor, (FET) device, and an associated method comprising:
a substrate 110;
a gallium nitride (GaN) structure 140, [0082] covering a portion of the substrate;
a gate metal layer 150/160 on top of the GaN structure;
wherein the gate metal layer comprises:
at least one first section 150 being formed from a first material composition [0085], and
a second section 160 being formed from a second material composition that is different from the first material composition [0088];
wherein a first interface between the GaN structure and the at least one first section of the gate metal layer has ohmic contact properties [0085]; and
wherein a second interface between the GaN structure and the second section of the gate metal layer has non-ohmic (Schottky, relevant to Claims 14 and 16) contact properties [0086].
Regarding Claims 7 and 15, Oh teaches the FET device of Claim 1 and method of Claim 14 wherein the at least one first section of the gate metal layer is formed from a first metal stack [0085], and/or wherein the second section of the gate metal layer is formed from a second metal stack [0088].
Regarding Claim 9, Oh teaches the FET device of Claim 1 wherein the GaN structure comprises a p-doped GaN, pGaN, layer [0085].
Regarding Claim 13, Oh teaches the FET device of Claim 1 wherein the FET device(10) is a GaN-gate high electron mobility transistor, HEMT,(HEMT) device.
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 3, 8 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Oh.
Regarding Claims 3 and 17, Oh teaches the FET device of Claim 1 and method of Claim 14 but does not explicitly teach that the first interface makes up less than 10% of a total interface area between the GaN structure and the gate metal layer, the total interface area comprising the first interface and the second interface.
However, Oh teaches that the ratio between the Schottky and Ohmic regions directly affects leakage current [0090] and is therefore a result effective variable that may be optimized by the person of ordinary skill to achieve application specific results (MPEP 2144.05(II)).
Regarding Claim 8, Oh teaches the FET device of Claim 7 but does not explicitly teach that the first metal stack and/or the second metal stack comprises any one of the following material combinations: Ni/Au, Ni/Ag, Pd/Au, Cr/Au, Pt/Au, Ti/Pt/Au, Ni/Si, W/Si, Ti/Al, Ti/Al/Ti, or TiN/Al/TiN. However, Oh teaches throughout the importance of the differing work function between the first 150 and second 160 portions of the gate metal and the depletion forming layer 140 in contact. Oh further teaches that either portion may be formed of various materials to achieve that end [0085,0088]. Therefore, the person of ordinary skill having the benefit of Oh may select materials according to the teachings of Oh to achieve the stated benefits and arrive at the various combinations claimed.
Conclusion
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/EVREN SEVEN/ Primary Examiner, Art Unit 2812