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 .
DETAILED ACTION
This office action is in response to the filing of the Applicant Arguments/Remarks Made in an Amendment on 08/04/2026. Currently, claims 1-3, 5-6, 9-12 and 15-25 are pending in the application. Claims 4, 7-8 and 13-14 have been cancelled and claims 19-25 have been added new.
Claim Objections
Claim 1 is objected to because of the following informalities: Where it recites “an SiC” in line 2 should be “a SiC”. Appropriate correction is required.
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 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 of this title, 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, 5-6, 9-12, 16, 17-18 and 20-24 are rejected under 35 U.S.C. 103 as being obvious over OKAMOTO et al (US 20100320505 A1) in view of HUANG et al (US 20100295100 A1).
Regarding claim 1, Figure 12 of OKAMOTO discloses a nitride semiconductor device comprising:
a SiC substrate (1A, [0074]) of a hexagonal crystal system ([0038], c-face sapphire substrate is a hexagonal crystal system) that has a first main surface (top surface of 1A in the Figure 12) and a second main surface (bottom surface of 1A in the Figure 12) at an opposite side thereof; and
a nitride epitaxial layer (3+4) comprising:
a first nitride semiconductor layer (3, [0038]) that is formed above the first main surface and constitutes an electron transit layer; and
a second nitride semiconductor layer (4, [0122]) that is disposed on the first nitride semiconductor layer, constitutes an electron supply layer, and is higher in bandgap than the first nitride semiconductor layer (AlGaN has higher bandgap than GaN);
an insulating film (12, [0066]) disposed on the second nitride semiconductor layer: a source electrode (5+13, [0066]), a drain electrode (6, [0063]), and a gate electrode (7, [0064]) that are disposed on the insulating film and respectively extend through contact holes formed in the insulating film (12) to contact the second nitride semiconductor layer (4);
a back electrode (35, [0152]) formed on the second main surface; and
a conductive member (8+34, [0152]) that electrically connects the source electrode to the back electrode, wherein the source electrode (5+13) comprises a main electrode portion (5+vertical portion of 13 covering 5) that contacts the second nitride semiconductor layer (4) and an extension portion (horizontal portion of 13 covering 8) extending on the insulating film, and the conductive member (8+34) penetrates through the SiC substrate (1A), the nitride epitaxial layer (17), and the insulating film (12), and is electrically connected to a lower surface of the extension portion (13) of the source electrode.
OKAMOTO does not teach that the gate electrode (7) extends through contact hole formed in the insulating layer (12).
However, HUANG is a pertinent art which teaches a nitride semiconductor wherein a source electrode (26+32+38), drain electrode (28+34) and a gate electrode (33) extends through contact hole formed in an insulating layer (18 +24) on a nitride semiconductor layer ([0023]-[0025]).
Thus, it would have been obvious to one of the ordinary skill in the art before the effective filing date of the claimed invention to modify the nitride semiconductor of OKAMOTO wherein the ate electrode (7) extends through contact hole formed in the insulating layer (12) according to the teaching of HUANG in order to connect the gate to other interconnecting structure for using the device in a system like radar ([0003], OKAMOTO).
Regarding claim 5, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, comprising: a semi-insulating nitride layer (17, N-face GaN with doping of Mg ) that is disposed between the SiC substrate (1A) and the first nitride semiconductor layer (3) and with which an acceptor concentration is higher than a donor concentration (since N-face GaN is used for layer 17) (please also see layer 14 in HUANG which is a semi-insulating layer).
Regarding claim 6, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 5, comprising: a buffer layer (16) that is disposed between the SiC substrate (1A) and the semi-insulating nitride layer (17) and is constituted of a nitride semiconductor (AlN, [0174]).
Regarding claim 9, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, wherein the first nitride semiconductor layer (3) is constituted of a GaN layer and the second nitride semiconductor layer (4) is constituted of an AlGaN layer.
Regarding claim 10, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 5, wherein the first nitride semiconductor layer (3) is constituted of a GaN layer, the second nitride semiconductor layer (4) is constituted of an AlGaN layer, and the semi-insulating nitride layer (17) is constituted of a GaN layer that contains carbon (HUANG teaches of doping with carbon in a semi-insulating layer 14, [0017] and [0019]).
Regarding claim 11, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 6, wherein the first nitride semiconductor layer (3) is constituted of a GaN layer, the second nitride semiconductor layer (4) is constituted of an AlGaN layer, the semi-insulating nitride layer (17) is constituted of a GaN layer that contains carbon (HUANG, [0017] and [0019]), and the buffer layer (16) is constituted of a laminated film of an AlN layer formed on the first main surface and an AlGaN layer that is laminated on the AlN layer ([008] and [0038]).
Regarding claim 12, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 6, wherein the first nitride semiconductor layer (3) is constituted of a GaN layer, the second nitride semiconductor layer (4) is constituted of an AlGaN layer, the semi-insulating nitride layer (17) is constituted of a GaN layer that contains carbon (HUANG, [0017] and [0019]), and the buffer layer (16) is constituted of an AlN layer or an AlGaN layer.
Regarding claim 16, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 3, comprising: a semi-insulating nitride layer (17) that is disposed between the SiC substrate (1A) and the first nitride semiconductor layer (3) and with which an acceptor concentration is higher than a donor concentration (since N-face GaN is used for layer 17).
Regarding claim 17, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 15, comprising: a buffer layer ([0008]) that is disposed between the SiC substrate (1A) and the semi-insulating nitride layer (17) and is constituted of a nitride semiconductor (AlGaN).
Regarding claim 18, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 16, comprising: a buffer layer (16, [0073]) that is disposed between the SiC substrate and the semi-insulating nitride layer (17) and is constituted of a nitride semiconductor.
Regarding claim 20, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, wherein the insulating film (12) is constituted of SiN ([0066]).
Regarding claim 21, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, further comprising: a hard mask layer (16) that is formed on the second main surface and has an opening portion at a position facing a portion of the extension portion of the source electrode, wherein the back electrode (35) is formed on a surface of the hard mask layer at an opposite side to the SiC substrate (1A).
Regarding claim 22, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, wherein the back electrode (35) covers a lower end surface of the conductive member (8+34).
Regarding claim 23, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, wherein the conductive member (8+34) is constituted of a barrier metal film (8) and a metal plug (34).
Regarding claim 24, Figure 12 of OKAMOTO discloses that the nitride semiconductor device according to Claim 1, wherein the main electrode portion (5 + portion of 13 covering 5) covers a source contact hole among the contact holes and a peripheral edge portion of the source contact hole at a front surface of the insulating film (12).
Claims 2-3, 15, 19 and 25 are rejected under 35 U.S.C. 103 as being obvious over OKAMOTO et al (US 20100320505 A1) in view of HUANG et al (US 20100295100 A1) as applied to claims above, and further in view of Tsujimura et al (US 20010008285 A1).
Regarding claims 2-3, 19 and 25, Figure 12 of OKAMOTO in view of HUANG do not explicitly teach that the nitride semiconductor device according to Claim 1, wherein the first main surface has an off angle that is inclined at an angle of not less than 1o and not more than 8o in a [11-20] direction with respect to a c-plane of the hexagonal crystal. Or
The nitride semiconductor device according to Claim 1, wherein the first main surface has an off angle that is inclined at an angle of not less than 2o and not more than 6o in a [11-20] direction with respect to a c-plane of the hexagonal crystal. Or
The nitride semiconductor device according to Claim 1, wherein the first main surface has an off angle of greater than 1o with respect to a c-plane of the hexagonal crystal. Or
The nitride semiconductor device according to Claim 1, wherein the SiC substrate is a 4H-SiC substrate.
However, Tsujimura is a pertinent art which teaches a nitride semiconductor formed on a SiC substrate, wherein Tsujimura teaches the substrate 11 may also be made of GaN, SiC, Si, Spinel, ZnO, GaAs or the like, instead of sapphire. Also, the substrate 11 may be of n-type, p-type or insulating. The plane orientation of the substrate 11 is not necessarily defined by a low-index plane. Alternatively, the plane orientation of the substrate 11 may be defined by an inclination in a certain direction. For example, if the substrate 11 is made of SiC, the zone axis thereof may be inclined from the (0001, c-plane) plane of 4H-SiC by two degrees in the [11-20] direction for reducing lattice mismatch with the layers grown on the substrate ([0027] and [0082]), wherein (0001) is the c-plane in the hexagonal crystal.
Thus, it would have been obvious to one of the ordinary skill in the art before the effective filing date of the claimed invention to use the SiC substrate which is a 4H-SiC of a hexagonal crystal system in the device of OKAMOTO in view of HUANG, wherein the first main surface has an off angle as claimed above according to the teaching of Tsujimura in order to reduce lattice mismatch between the substrate (1010, Figure 11 of Saxler) and the layers grown on the substrate ([0081]-[0082] of Tsujimura).
Regarding claim 15, Figure 12 of OKAMOTO in view of HUANG teach that the nitride semiconductor device according to Claim 2, comprising: a semi-insulating nitride layer (17) that is disposed between the SiC substrate (1A) and the first nitride semiconductor layer (3) and with which an acceptor concentration is higher than a donor concentration (since n-face GaN is used for layer 17).
Response to Arguments
Applicant’s arguments/amendments regarding the rejection of claims 1-3, 5-6, 9-12, 15-25, filed on 08/04/2026, have been fully considered but arguments are moot because newly added limitation to the claim (s) requires a new ground of rejection necessitated by amendments.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KHAJA AHMAD whose telephone number is (571)270-7991. The examiner can normally be reached on Monday to Friday from 8:00 AM to 5:00 PM (Eastern Time).
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, GAUTHIER STEVEN B, can be reached on (571)270-0373. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/KHAJA AHMAD/
Primary Examiner, Art Unit 2813
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