DETAILED ACTION
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.
Claim(s) 1, 3, and 5 thru 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wong et al. Enhancement-Mode β -Ga2O3 Current Aperture Vertical MOSFETs With N-Ion-Implanted Blocker, Vol. 41, No. 2 pages 296-299, February 2020 as disclosed by the applicant’s IDS filed 10/26/23 in view of Naylor et al. US 2021/0083122 A1. Wong discloses (see, for example, Fig. 1) a semiconductor device comprising at least: a crystalline oxide semiconductor layer including a Si+-implanted channel layer, a n- -Ga2O3 drift layer, and a source region n++/naccess; a gate electrode G arranged over the channel layer across a gate insulating film; an N++- implanted current blocking region arranged between the channel layer and the n- -Ga2O3 drift layer; and a source electrode S provided on the source region, the N++- implanted current blocking region being composed of a high-resistance layer, the source electrode S forming a contact with the N++- implanted current blocking region. Wong does not expressly disclose the oxide semiconductor layer being crystalline. However, Naylor discloses (see, for example, FIG. 10) a semiconductor device 1001 comprising an oxide semiconductor layer 210. In paragraph [0037], and [0033], Naylor discloses using a material that is crystalline, and may include metal oxides. It would have been obvious to one of ordinary skill in the art to have the oxide semiconductor layer being crystalline in order to have an ordered structure with minimal defects that provides better electrical performance and stability.
Regarding claim 3, see, for example, paragraph [0033] wherein Naylor discloses metal oxide including In, Ga, etc.
Regarding claims 5-6, see, for example, page 297, lines 10-14 wherein Wong discloses a nitrogen (i.e. dopant) and a peak dopant concentrations 1.5 x 1018 cm-3 (i.e. equal to or greater than 1.0 x 1017/cm3.
Regarding claim 7, see, for example, Fig. 1 wherein Wong discloses an N++- implanted current blocking region.
Regarding claim 8, Wong in view of Naylor does not specifically disclose the electron trap density in the current blocking region being equal to or greater than 4.0 x 1018/cm3; however, it would have been obvious to one of ordinary skill in the art to have the electron trap density in the current blocking region being equal to or greater than 4.0 x 1018/cm3 in order to improve electron mobility and decrease leakage current, and since it has been held that discovering the optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F. 2d 272, 205 USPQ 215 (CCPA 1980).
Regarding claim 9, see, for example, Fig. 1 wherein Wong discloses a transistor.
Regarding claims 10-11, Wong in view of Naylor does not disclose a power converter or control system; however, it would have been obvious to one of ordinary skill in the art to have the semiconductor device in a power converter or control system in order to utilize the semiconductor device in more robust electronic devices according to the preferences of the user.
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wong et al. Enhancement-Mode β -Ga2O3 Current Aperture Vertical MOSFETs With N-Ion-Implanted Blocker, Vol. 41, No. 2 pages 296-299, February 2020 in view of Naylor et al. US 2021/0083122 A1 as applied to claims 1, 3-5, and 5-11 above, and further in view of Hashigami et al. US 2022/0058424 A1. Wong in view of Naylor does not expressly disclose a corundum structure. However, Hashigami discloses (see, for example, paragraph [0067]) using a semiconductor film mainly made of a corundum structure. It would have been obvious to one of ordinary skill in the art to have a corundum structure in order to have a low resistance including excellent electrical properties, and since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
Allowable Subject Matter
Claim 2 is 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.
The following is a statement of reasons for the indication of allowable subject matter: The references of record, either singularly or in combination, do not teach or suggest at least a semiconductor device comprising at least: a crystalline oxide semiconductor layer including a current blocking region arranged between the channel layer and the drift layer; and a source electrode provided on the source region, the current blocking region being composed of a high-resistance layer, the source electrode forming a contact with the current blocking region, wherein the source electrode directly contacts the current blocking region.
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Eugene Lee
December 19, 2025
/EUGENE LEE/Primary Examiner, Art Unit 2815