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 § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-3, 5-10 and 12-21 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
The last three lines of claims 1 and 14 have been amended to be -- an oxygen concentration profile corresponding to an inside of the first portion has a peak at a position between a boundary portion between the first portion and the semiconductor layer and a center position of the first portion in the first direction --. In page one of the remarks filed on 08/21/2026, the applicant stated “support for the amended and new claims can be found at least at paragraphs [0032], [0074], [0093], and [0100]- [0107] and FIG. 6 of the published version of the application (US 2024/0079469). No new matter is presented.” These paragraphs along with Fig. 6 were carefully considered, however the language of the current amendment does not appear to have adequate support in the specification. The specification says “oxygen (O) contained in the first portion 151 of the Schottky electrode 15 selectively thickens in the vicinity of the boundary portion 156. In other words, oxygen (O) contained therein is in a more thickened state on the side closer to the boundary portion 156 than to a central portion in the depth direction (rightward direction of the horizontal axis) of the first portion 151 of FIG. 6. More specifically, in the first portion 151, the concentration profile 173 of oxygen (O) has a peak 177 on the side closer to the boundary portion 156 than to the central portion in the depth direction of the first portion 151.” For the purposes of the art rejection below this amendment has been interpreted to be the same as the above-mentioned underlined quote.
Claims 2-3, 5-10, 12-13 and 15-21 are included likewise as they depend from claim 1 or 14.
DETAILED ACTION
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 5, 7-10, 12-15, 17-18 and 20-21 are rejected under 35 U.S.C. 103 as being unpatentable over Ichikawa (Pub. No. US 2019/0109005 A1) in view of Koumoto et al. (Pub. No. US 2010/0032839 A1, herein Koumoto).
Regarding claim 1, Ichikawa discloses semiconductor device comprising: a semiconductor layer 42 (Ichikawa: Fig. 1 and paragraph [0038]); and a Schottky electrode 34 that is formed at a first surface of the semiconductor layer and that forms a Schottky junction portion between the semiconductor layer and the Schottky electrode (Ichikawa: Fig. 1 and paragraph [0040]), wherein the Schottky electrode has a first portion that is selectively formed near the first surface of the semiconductor layer in a thickness direction of the Schottky electrode and that is made of Mo containing oxygen (Ichikawa: Figs. 1, 9 and paragraphs [0011]-[0012], [0034]-[0035]).
Ichikawa introduces Ti for electrode 32 but does not specifically state the metal used for the Schottky electrode is Ti containing oxygen, and when an analysis is made in a first direction from the Schottky electrode toward the semiconductor layer according to a predetermined quantitative-analysis method, an oxygen concentration profile corresponding to an inside of the first portion has a peak at a position closer to a boundary portion between the first portion and the semiconductor layer than a center position of the first portion in the first direction.
However, to provide support for the assertion made in the previous office actions regarding the rejection of the original claim 4’s limitations (now added to claim 1), Koumoto, in Fig. 10 and paragraphs [0064]-[0065], [0177]-[0178], teaches the oxide of Ti distributes over a region ranging from the interface between the electrode 14 and the semiconductor substrate 11 to the topmost portion of the electrode 14; in the electrode structure before being annealed, the peak concentration of O resides closer to the interface between the GaN substrate and the electrode for further reduction in contact resistance between the semiconductor layer and the electrode.
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Furthermore, a Schottky electrode is commonly evaluated using predetermined quantitative analysis methods to extract parameters such as barrier height, ideality factor, and series resistance. These analyses are typically based on standard semiconductor equations (I-V curve fitting, C-V analysis, Richardson Plot Analysis, Cheung’s method for series resistance extraction, Norde Method) derived from thermionic emission theory and measured I-V or C-V characteristics. Because the governing equations and extraction techniques are well established, a skilled person can routinely calculate the electrode characteristics from measured data. Therefore, the calculations are often considered obvious and straightforward in semiconductor device analysis.
Therefore, given the teachings of Koumoto, a person having ordinary skill in the art before the effective filing date of the claimed invention would have readily recognized the desirability and advantages of modifying Ichikawa in view of Koumoto by employing the peak oxide concentration of Ti closer to the boundary of the semiconductor and electrode interface.
Regarding claim 5, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 1, wherein a concentration at the peak of the oxygen concentration profile is not less than 2.0 atm% and not more than 10.0 atm% (Koumoto: Figs. 10-12 and paragraphs [0021], [0067], [0068]). The claimed concentration range is recognized as a result-effective variable, i.e., a variable which achieves a recognized result. Therefore, it would have been an obvious matter of design choice bounded by well-known manufacturing constraints and ascertainable by routine experimentation and optimization to choose the particular claimed range because applicant has not disclosed that the limitations are for a particular unobvious purpose, produce an unexpected result, or are otherwise critical, and it appears prima facie that the process would possess utility using another range. The claim(s) is(are) obvious without showing that the claimed range(s) achieve unexpected results relative to the prior art range. See In re Aller, 105 USPQ 233 (CCPA 1955) and 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).
Regarding claim 7, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 1, wherein the semiconductor layer does not contain oxygen near the first surface in the Schottky junction portion (Ichikawa: Figs. 1, 9 and paragraphs [0034]-[0040] and Koumoto: Figs. 10-12 and paragraphs [0064]-[0065], [0185], [0188]).
Regarding claim 8, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 1, further comprising a front surface electrode 30 that is formed on the Schottky electrode and that is made of an Al alloy or Al (Ichikawa: Figs. 1, 9 and paragraph [0040]).
Regarding claim 9, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 8, wherein the Al alloy includes at least one among an AlCu alloy, an AlSi alloy, and an AlSiCu alloy (Ichikawa: Figs. 1, 9 and paragraph [0040]). See In re Leshin, 125 USPQ 416 (CCPA 1960) where the court stated that a selection of a material on the basis of suitability for intended use of an apparatus would be entirely obvious.
Regarding claim 10, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 1, wherein the semiconductor layer includes a first conductivity type semiconductor layer 42, and the semiconductor device further comprises a second conductivity type impurity region 38 that is selectively formed at the first surface of the semiconductor layer so as to be contiguous to the Schottky electrode and that makes a p-n junction between the semiconductor layer and the second conductivity type impurity region (Ichikawa: Figs. 1, 9 and paragraph [0046]).
Regarding claim 12, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 10, wherein the first conductivity type is an n-type, and the second conductivity type is a p-type (Ichikawa: Figs. 1, 9 and paragraph [0046]).
Regarding claim 13, Ichikawa in view of Koumoto teaches the semiconductor device according to Claim 1, wherein the semiconductor layer includes a SiC semiconductor layer (Ichikawa: Figs. 1, 9 and paragraph [0007]).
Regarding claim 14, Ichikawa discloses a method for manufacturing a semiconductor device, the method comprising: a step of introducing oxygen into a first surface of the semiconductor layer 42 having the first surface; a step of forming a Schottky electrode 34 having a first portion made of a metal that is contiguous to the first surface of the semiconductor layer by depositing the metal on the first surface of the semiconductor layer; and a step of diffusing the oxygen introduced into the semiconductor layer into the first portion of the Schottky electrode by annealing treatment (Ichikawa: Figs. 1, 9 and paragraphs [0011]-[0012], [0034]-[0035]).
Ichikawa introduces Ti for electrode 32 but does not specifically state the metal used for the Schottky electrode is Ti containing oxygen, and when an analysis is made in a first direction from the Schottky electrode toward the semiconductor layer according to a predetermined quantitative-analysis method, an oxygen concentration profile corresponding to an inside of the first portion has a peak at a position closer to a boundary portion between the first portion and the semiconductor layer than a center position of the first portion in the first direction.
However, to provide support for the assertion made in the previous office actions regarding the rejection of the original claim 4’s limitations (now added to claim 1), Koumoto, in Fig. 10 and paragraphs [0064]-[0065], [0177]-[0178], teaches the oxide of Ti distributes over a region ranging from the interface between the electrode 14 and the semiconductor substrate 11 to the topmost portion of the electrode 14; in the electrode structure before being annealed, the peak concentration of O resides closer to the interface between the GaN substrate and the electrode for further reduction in contact resistance between the semiconductor layer and the electrode.
Furthermore, a Schottky electrode is commonly evaluated using predetermined quantitative analysis methods to extract parameters such as barrier height, ideality factor, and series resistance. These analyses are typically based on standard semiconductor equations (I-V curve fitting, C-V analysis, Richardson Plot Analysis, Cheung’s method for series resistance extraction, Norde Method) derived from thermionic emission theory and measured I-V or C-V characteristics. Because the governing equations and extraction techniques are well established, a skilled person can routinely calculate the electrode characteristics from measured data. Therefore, the calculations are often considered obvious and straightforward in semiconductor device analysis.
Therefore, given the teachings of Koumoto, a person having ordinary skill in the art before the effective filing date of the claimed invention would have readily recognized the desirability and advantages of modifying Ichikawa in view of Koumoto by employing the peak oxide concentration of Ti closer to the boundary of the semiconductor and electrode interface.
Regarding claim 15, the use of the particular type of cleaning and washing process by Applicant is considered to be nothing more than the use of one of numerous and well-known alternate types of cleaning process that a person having ordinary skill in the art would have been able to provide using routine experimentation; as the grown oxide consumes surface contaminations and defects, which are then removed when the oxide is stripped, whereas the liquid washing is a simple, low cost, scalable and compatible with a wide range of materials and process flows. Therefore, a person having ordinary skill in the art before the effective filing date of the claimed invention would have readily recognized the desirability and advantages of washing the first surface of the semiconductor layer by means of a chemical liquid, wherein the step of introducing oxygen includes a step of introducing oxygen into the semiconductor layer by irradiating oxygen plasma toward the first surface of the semiconductor layer washed by the chemical liquid.
With respect to claims 17-18, Koumoto in paragraphs [0066] and [0081] discusses the thicknesses for the metal oxide layer but does not specifically state the claimed ranges. However, the claimed thickness ranges are recognized as a result-effective variable, i.e., a variable which achieves a recognized result. Therefore, it would have been an obvious matter of design choice bounded by well-known manufacturing constraints and ascertainable by routine experimentation and optimization to choose the particular claimed range because applicant has not disclosed that the limitations are for a particular unobvious purpose, produce an unexpected result, or are otherwise critical, and it appears prima facie that the process would possess utility using another range. The claim(s) is(are) obvious without showing that the claimed range(s) achieve unexpected results relative to the prior art range. See In re Aller, 105 USPQ 233 (CCPA 1955) and 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).
Regarding claim 20, Ichikawa in view of Koumoto teaches the method for manufacturing a semiconductor device according to Claim 14, wherein the step of introducing oxygen includes selectively introducing the oxygen into a surface layer portion of the first surface of the semiconductor layer (Ichikawa: Figs. 1, 9 and paragraphs [0034]-[0040] and Koumoto: Figs. 10-12 and paragraph [0032]).
Regarding claim 21, Ichikawa in view of Koumoto teaches the method for manufacturing a semiconductor device according to Claim 15, wherein the oxygen plasma is irradiated at a pressure of not less than 10 Pa and not more than 1000 Pa (Ichikawa: paragraph [0050]). The claimed pressure range is recognized as a result-effective variable, i.e., a variable which achieves a recognized result. The oxygen plasma is irradiated at a pressure of 10-1000 Pa because this pressure range provides a suitable balance between plasma generation and reactive-species density, whereas pressure below 10 Pa may result in insufficient plasma density and reactive oxygen species, while pressure above 1000 Pa may increase collisional losses and reduce plasma uniformity and treatment efficiency. Therefore, it would have been an obvious matter of design choice bounded by well-known manufacturing constraints and ascertainable by routine experimentation and optimization to choose the particular claimed range because applicant has not disclosed that the limitations are for a particular unobvious purpose, produce an unexpected result, or are otherwise critical, and it appears prima facie that the process would possess utility using another range. The claim(s) is(are) obvious without showing that the claimed range(s) achieve unexpected results relative to the prior art range. See In re Aller, 105 USPQ 233 (CCPA 1955) and 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).
Claims 2, 16 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Ichikawa in view of Koumoto, as applied above, and further in view of Emiko (JP 2002217210 A).
Regarding claim 2, the previous combination is silent about the Schottky electrode having a second portion that is formed on the first portion and that is made of Ti and N.
However, in the same field of endeavor, Emiko states “a method of manufacturing a semiconductor device, comprising: forming a first layer containing titanium and nitrogen or oxygen or both on the semiconductor region to form the Schottky barrier electrode… A first layer forming a Schottky barrier at an interface with the semiconductor region; and a second layer stacked on an upper surface of the first layer, wherein the first layer is nitrogen or oxygen or nitrogen and oxygen preferably, the second layer is made of a metal material having a characteristic of making low-resistance contact with the semiconductor region...a first layer forming a Schottky barrier at an interface with the semiconductor region; and a second layer stacked on an upper surface of the first layer, wherein the first layer includes titanium and nitrogen or oxygen or containing both of these, and having a titanium content of 50 to 90% by weight”.
Therefore, given the teachings of Emiko, a person having ordinary skill in the art before the effective filing date of the claimed invention would have readily recognized the desirability and advantages of modifying the previous combination in view of Emiko by employing the Schottky electrode having a second portion that is formed on the first portion and that is made of Ti and N.
Regarding claim 16, Ichikawa in view of Koumoto and further in view of Emiko teaches the method for manufacturing a semiconductor device according to Claim 14, wherein the step of forming a Schottky electrode includes a step of forming a second portion made of Ti and N on the first portion by additionally depositing Ti in an N2 atmosphere after the first portion is formed (Ichikawa: Figs. 1, 9 and paragraph [0007]).
Regarding claim 19, the applicant is referred to the rejections applied to claims 17 and 18 above.
Allowable Subject Matter
Claims 3 and 6 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.
Claim 11 is allowed.
The following is a statement of reasons for the indication of allowable subject matter:
With respect to claim 3, the prior art of record alone or in combination do not teach or fairly suggest, in combination with other elements of the claims, wherein an oxygen concentration near the Schottky junction portion is higher than both an oxygen concentration in the vicinity of an interface between the first portion and the second portion and an average oxygen concentration of the semiconductor layer.
With respect to claim 6, the prior art of record alone or in combination do not teach or fairly suggest, in combination with other elements of the claims, further comprising an insulation layer that is formed at the first surface of the semiconductor layer and that has an opening from which the first surface is partially exposed, wherein the Schottky electrode includes a first covering portion that covers the first surface of the semiconductor layer in the opening of the insulation layer and a second covering portion that is formed outside the opening of the insulation layer and that covers the insulation layer, and the first portion selectively contains oxygen in the first covering portion of the Schottky electrode, and does not contain oxygen in the second covering portion.
With respect to claim 11, the prior art of record alone or in combination do not teach or fairly suggest, in combination with other elements of the claims, further comprising a lattice defect region that is selectively formed at the first surface of the semiconductor layer so as to be contiguous to the Schottky electrode and that has lattice defects more than the semiconductor layer, and the impurity region includes a first region formed inside the lattice defect region so as to be contiguous to the lattice defect region.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Response to Arguments
Applicant’s arguments with respect to claims 1-2, 5, 7-10 and 12-21 have been fully considered, but are found to be moot in view of the new grounds of rejection.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MALIHEH MALEK whose telephone number is (571)270-1874. The examiner can normally be reached M/T/W/R/F, 8:30-5.
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September 5, 2026
/MALIHEH MALEK/Primary Examiner, Art Unit 2813
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