DETAILED ACTION
This Office Action is in response to Application filed June 1, 2023.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Objections
Claims 1 and 18 are objected to because of the following informalities:
On line 4 of claim 1, “that” should be replaced with “a band gap”, because (a) the pronoun “that” implies “the band gap” as is the case with the pronoun “that” recited on line 8 of claim 1, and (b) therefore, when strictly interpreted, “that” or “the band gap” of the electron transit layer lacks the antecedent basis.
On line 8 of claim 1, “that” should be replaced with “the band gap”.
On lines 9-10 of claim 18, “concentration” should be replaced with “a concentration”.
Appropriate correction is required.
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 3-6, 12, 13 and 18-20 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.
(1) Regarding claim 3, it is not clear what the limitation “the zinc is higher in concentration than the magnesium” recited on line 6 suggests, because (a) it is not clear what “the zinc” and “the magnesium” each refers to since as shown below, the concentration of zinc and the concentration of magnesium vary throughout the doped region D1, which appears to correspond to Applicant’s gate layer,
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(b) in this case, the limitations “the zinc” and “the magnesium”, whose concentrations are compared in claim 3, would lack the antecedent basis since it is not clear which concentration of “the zinc” and which concentration of “the magnesium” are compared in claim 3, (c) as illustrated in Fig. 2 of current application, it appears that a concentration of “the zinc” is the same with a concentration of “the magnesium” at or near the claimed second surface of the first region, and (d) therefore, depending on how “the zinc” and “the magnesium” and their concentrations are defined, even Applicant’s measurement result shown in Fig. 2 of current application would not read on claim 3.
(2) Further regarding claim 3, it is not clear what “the gate layer” recited on line 3 of claim 3 refers to, because (a) even though the term “a gate layer” recited on line 6 of claim 1 can be broadly interpreted, Applicant further claims that “in the first region” of the gate layer “the zinc is higher in concentration than the magnesium” on line 6 of claim 3,
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(b) it appears that Applicant had intended to claim that the doped region D1 shown in Fig. 2 of current application is the claimed “gate layer”, (c) however, the doped region D1 shown in Fig. 2 of current application is not exactly the claimed “gate layer” in the claimed nitride semiconductor device since (i) the oval-shaped region illustrated above would also function as the bottommost portion of the gate layer since the oval-shaped region illustrated above is formed of AlGaN, which is the material composition of the electron supply layer as also recited in claims 9, 15 and 19, doped with diffused Mg and Zn, and (ii) in semiconductor industry, a p-type AlGaN layer doped with Mg and/or Zn has also been commonly employed as a gate layer in addition to a p-type GaN layer doped with Mg and/or Zn in manufacturing HEMT devices, (d) in other words, in an actual nitride semiconductor device, the oval-shaped region illustrated above would correspond to the claimed first region, but in this actual first region, a concentration of zinc and a concentration of magnesium are more or less the same, and (e) therefore, it appears that claim 3 is directed to Applicant’s design or intention of the claimed nitride semiconductor device, which cannot be manufactured and/or is distinct from an actual nitride semiconductor device structure, rendering claim 3 indefinite since it is not clear whether claim 3 is directed to an actually observable feature of the claimed nitride semiconductor device where there is no diffusion whatsoever of the zinc and magnesium, or claim 3 is directed to a feature that Applicant intended to create, but cannot exactly be observed since the topmost portion of the claimed electron supply layer would be converted into the bottommost portion of the claimed gate layer as illustrated in Fig. 2 of current application.
Claims 4-6 and 13 depend on claim 3, and therefore, claims 4-6 and 13 are also indefinite.
(3) Regarding claim 12, claim 12 including the limitation “in the first region, the zinc is higher in concentration than the magnesium” recited on line 5, which is identical to the limitation recited on line 6 of claim 3, is indefinite for the same reasons stated above with regard to claim 3.
(4) Regarding claim 18, claim 18 including the limitation “in the first region, the zinc is higher in concentration than the magnesium” recited on line 8, which is identical to the limitation recited on line 6 of claim 3 and on line 5 of claim 12, and the limitation “in the second region, concentration of the magnesium is higher than or equal to concentration of the zinc” recited on lines 9-10, which is substantially identical to the limitation recited on line 6 of claim 3 and on line 5 of claim 12, is indefinite for the same reasons stated above with regard to claim 3; the Examiner notes that as illustrated below, in addition to the oval-shaped region, the rectangular-shaped region may also function as the claimed “gate layer”, but in the rectangular-shaped region, a concentration of zinc can also be higher than a concentration of magnesium in certain areas. Claims 19 and 20 depend on claim 18, and therefore, claims 19 and 20 are also indefinite.
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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)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(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 and 9-11 are rejected under 35 U.S.C. 102(a)(1) or (a)(2) as being anticipated by Okita et al. (US 2020/0119178)
Regarding claim 1, Okita et al. disclose a nitride semiconductor device (Fig. 1), comprising: an electron transit layer (3; GaN) formed from a nitride semiconductor ([0043]); an electron supply layer (4; AlGaN) ([0043]) formed on the electron transit layer, the electron supply layer being formed from a nitride semiconductor (AlGaN) having a band gap that is inherently larger than that of the electron transit layer, because an AlGaN layer inherently has a band gap larger than a GaN layer since the Al atoms incorporated in the AlGaN layer renders its band gap larger than the GaN layer; a gate layer (composite layer of 5 and 6) ([0044]-[0045]) formed on the electron supply layer (3), the gate layer being formed from a nitride semiconductor ([0044]-[0045]) including an acceptor impurity (Mg in third nitride semiconductor layer 5 and Zn in high resistance region 6) ([0046]-[0047]) and having a band gap that is smaller than that of the electron supply layer, because (a) Okita et al. disclose that the gate layer is formed of a p-GaN ([0044]), which inherently has a band gap smaller than a band gap of AlGaN constituting the electron supply layer 4; a gate electrode (7) ([0045]) formed on the gate layer; and a source electrode (9) ([0045]) and a drain electrode (10) that are in contact with the electron supply layer (4), wherein the acceptor impurity includes zinc and magnesium ([0046]-[0047]), the zinc inherently has a concentration profile in a thickness-wise direction of the gate layer (composite layer of 5 and 6), because (a) Applicant does not specifically claim what the “concentration profile” refers to, and (b) therefore, any arbitrary concentration profile of zinc in the gate layer would be present “in a thickness-wise direction of the gate layer,” the magnesium inherently has a concentration profile in the thickness-wise direction of the gate layer, because (a) Applicant does not specifically claim what the “concentration profile” refers to, and (b) therefore, any arbitrary concentration profile of magnesium in the gate layer would be present “in a thickness-wise direction of the gate layer,” and the concentration profile of the zinc differs from the concentration profile of the magnesium, because zinc is (primarily) disposed in the high resistance region 6 of the gate layer and magnesium is (primarily) disposed in the third nitride semiconductor layer 5 of the gate layer.
Regarding claims 9-11, Okita et al. further disclose that the electron transit layer (3) is formed from GaN, the electron supply layer (4) is formed from AlGaN, and the gate layer (composite layer of 5 and 6) is formed from GaN ([0046]) including the acceptor impurity, because (a) Okita et al. disclose that the third nitride semiconductor layer 5 is formed of p-GaN, and (b) Okita et al. further disclose that “Nitride semiconductor device 100 has high resistance region 6 which contains a second impurity element and has a specific resistance higher than a specific resistance of third nitride semiconductor layer 5 in a part of third nitride semiconductor layer 5 containing the p-type first impurity element (emphasis added)” in paragraph [0045] (claim 9), the gate layer (composite layer of 5 and 6) has a thickness that is greater than or equal to 80 nm and less than or equal to 150 nm, because Okita et al. further disclose that the thickness of the third nitride semiconductor layer 5 is preferably 100 nm in paragraph [0046] (claim 10), and the nitride semiconductor device (Fig. 1) includes a normally-off transistor, because the two-dimensional electron gas 8 is interrupted without any biases applied as shown in Fig. 1 of Okita et al. (claim 11).
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 2 and 15-17 are rejected under 35 U.S.C. 103 as being unpatentable over Okita et al. (US 2020/0119178) The teachings of Okita et al. are discussed above.
Regarding claim 2, Okita et al. differ from the claimed invention by not showing that a maximum concentration of the zinc in the gate layer is greater than or equal to 1×10¹⁸ cm⁻³ and less than or equal to 2×10¹⁹ cm⁻³, and a maximum concentration of the magnesium in the gate layer is greater than or equal to 1×10¹⁹ cm⁻³ and less than or equal to 2×10¹⁹ cm⁻³.
Okita et al. further disclose in paragraph [0046] that “When the p-type first impurity element is Mg, it is only necessary that the concentration is in the range of 1×1019 cm-3 to 10×1019 cm-3, preferably 5×1019 cm-3”, and in paragraph [0047] that “It is only necessary that the second impurity element contained in high resistance region 6 is at least one of F, B, Ar, He, Fe, Cr, Zn, Ca and Ti, for example, any element that completely inactivates an n-type or p-type nitride semiconductor and increases resistance such as F and Fe.”
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that a maximum concentration of the zinc in the gate layer can be greater than or equal to 1×10¹⁸ cm⁻³ and less than or equal to 2×10¹⁹ cm⁻³, and a maximum concentration of the magnesium in the gate layer can be greater than or equal to 1×10¹⁹ cm⁻³ and less than or equal to 2×10¹⁹ cm⁻³, because (a) the claimed maximum concentration of the magnesium overlaps with the concentration of magnesium disclosed by Okita et al., and therefore, when the concentration of the magnesium disclosed by Okita et al. is at or near the lower limit of the range “1×1019 cm-3 to 10×1019 cm-3” disclosed by Okita et al., which would have been obvious to one of ordinary skill in the art, the maximum concentration of the magnesium disclosed by Okita et al. would satisfy the claim limitation directed to the maximum concentration of the magnesium, (b) in addition, the maximum concentration of zinc in the nitride semiconductor device disclosed by Okita et al. can be also optimized to obtain desired resistance/resistivity of the high resistance region 6 to improve performance of the nitride semiconductor device disclosed by Okita et al., and (c) the claim is prima facie obvious without showing that the claimed ranges of the maximum concentrations achieve unexpected results relative to the prior art range. In re Woodruff, 16 USPQ2d 1935, 1937 (Fed. Cir. 1990). See also In re Huang, 40 USPQ2d 1685, 1688 (Fed. Cir. 1996) (claimed ranges of a result effective variable, which do not overlap the prior art ranges, are unpatentable unless they produce a new and unexpected result which is different in kind and not merely in degree from the results of the prior art). See also In re Boesch, 205 USPQ 215 (CCPA) (discovery of optimum value of result effective variable in known process is ordinarily within skill of art) and In re Aller, 105 USPQ 233 (CCPA 1955) (selection of optimum ranges within prior art general conditions is obvious).
Regarding claims 15-17, Okita et al. further disclose that the electron transit layer (3) is formed from GaN, the electron supply layer (4) is formed from AlGaN, and the gate layer (composite layer of 5 and 6) is formed from GaN including the acceptor impurity, see the explanation with regard to claim 9 (claim 15), the gate layer (composite layer of 5 and 6) has a thickness that is greater than or equal to 80 nm and less than or equal to 150 nm, see the explanation with regard to claim 10 (claim 16), and the nitride semiconductor device includes a normally-off transistor, see the explanation with regard to claim 11 (claim 17).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Chiang et al. (US 10,714,607)
Chou et al. (US 11,527,606)
Buckley et al. (US 2019/0334022)
Hikita et al. (US 9,577,084)
Lidow et al. (US 8,436,398)
Fujimoto (US 9,412,856)
Kim et al. (US 9,117,890)
Okita et al. (US 11,171,228)
Banerjee et al. (US 9,960,265)
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAY C KIM whose telephone number is (571) 270-1620. The examiner can normally be reached 8:00 AM - 6:00 PM EST.
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/J.K./Primary Examiner, Art Unit 2815 January 7, 2026
/JAY C KIM/Primary Examiner, Art Unit 2815