DETAILED ACTION
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 .
Response to Arguments
Regarding the drawing objections under 37 CFR 1.83(a)—directed toward the features recited in Claim 5—set forth in the previous Office Action filed 31 March 2026, on page 6 of the previous reply filed 1 June 2026, Applicant asserts:
The Examiner objects that the "separating layer" recited in Claim 5 is not shown in Fig. 3a. Applicant respectfully submits that this objection is improper because the separating layer is clearly shown in Fig. 7b of the application drawings, which is expressly part of the elected Species I disclosure.
Applicant’s arguments in this regard have been fully considered and are found persuasive. Therefore, the associated objection is withdrawn.
Regarding the drawing objections under 37 CFR 1.83(a)—directed toward the features recited in Claims 7 & 15—set forth in the previous Office Action filed 31 March 2026, these objections are withdrawn, as the associated claims have been cancelled.
Regarding the objection to the specification—directed toward the title of the invention—set forth in the previous Office Action filed 31 March 2026, this objection is maintained, as the amendment provided in the reply filed 1 June 2026 was not accompanied with by an amendment to the specification reflecting said change in title.
Regarding the rejection of Claim 1 & 18 under 35 U.S.C. 102 set forth in the previous Office Action filed 31 March 2026, on page 7 of the previous reply filed 1 June 2026, Applicant asserts:
OH fails to anticipate amended claim 1 because OH does not disclose varying the p-dopant concentration.
Applicant’s arguments in this regard have been fully considered but are moot, as these claims now stand rejected as being unpatentable under OH in view of OKAWA where OKAWA teaches said variation in the p-dopant concentration.
Regarding the present rejection of Claim 1 under 35 U.S.C. 103 set forth below, Applicant asserts:
Applying OKAWA to OH does not result in the claimed embodiment of amended claim 1.
In support of this assertion, Applicant argues:
Amended claim 1 requires…the p-dopant concentration decreases continuously as a function of depth…[and] OKAWA does not teach or suggest this depth-dependent vertical gradient.
Applicant’s argument in this regard has been fully considered but is not found persuasive, as Applicant’s argument is not commensurate in scope with the language of Claim 1. Specifically, requiring “the p-dopant concentration decreases continuously as a function of depth” as argued is not commensurate in scope with requiring “a concentration of p-dopants in the pGaN layer decreases as a function of depth”, as the latter may include discontinuous functions of depth—such as illustrated in Fig. 9 of OKAWA and the associated prior rejection below—under a broadest reasonable interpretation. Therefore, amending Claim 1 to require “a concentration of p-dopants in the pGaN layer decreases as a function of depth” is not deemed to patentably distinguish Applicant’s claimed invention from the known invention of OH in view of OKAWA.
In support of this same assertion, Applicant further argues:
If one having ordinary skill in the art were to apply OKAWA's teachings to the physical protrusion 140a of OH, the result would merely be a discrete, highly-doped block implanted at the top of the protrusion. The prior art combination completely lacks any teaching or suggestion of a pGaN layer with a continuous vertical doping gradient.
Applicant’s argument in this regard has been fully considered but is not found persuasive for the same reasons as above, regarding the scope of Applicant’s argument versus the scope of the language of amended Claim 1 as well as discontinuous functions being functions under a broadest reasonable interpretation. Therefore, amending Claim 1 as provided by Applicant in the aforementioned reply is not deemed to patentably distinguish Applicant’s claimed invention from the known invention of the prior art of record.
Regarding the rejection of Claim 3 under 35 U.S.C. 103 set forth in the previous Office Action filed 31 March 2026, on page 8 of the previous reply filed 1 June 2026, Applicant asserts:
OH does not disclose all features of amended independent claim 1. Therefore, claim 3, which depends from claim 1, is allowable for at least the same reasons claim 1 is allowable over OH.
Applicant’s arguments in this regard have been fully considered but are moot as amended Claim 1 now stands rejected as being unpatentable over OH in view of OKAWA as necessitated by Applicant’s amendments.
Regarding the rejections of Claims 8 & 15 under 35 U.S.C. 103 set forth in the previous Office Action filed 31 March 2026, Applicant’s traversal on page 8 of the reply filed 1 June 2026 has been fully considered but is moot, as these claims have been cancelled.
Regarding the rejections of Claims 16 & 19 under 35 U.S.C. 103 set forth in the previous Office Action filed 31 March 2026, Applicant’s traversal on page 8 of the reply filed 1 June 2026 has been fully considered but is not found persuasive, as neither the respective base claims of Claims 16 & 19 nor the claims themselves are not found allowable over OH in view of OKAWA, as stated above.
Specification
Please, provide an amendment to the specification reflecting the change in title provided in the reply filed 1 June 2026.
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.
Claims 1 & 18—and their respective dependent claims—are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Regarding Claim 1,
Lin. 15 – 16 recite the limitation “the second interface is located at a depth within the pGaN layer having a lower concentration of p-dopants than the first interface”. However, an interface of a layer is always located at a surface of said layer. Therefore, the meaning of the requirement “the second interface is…within the pGaN layer” (emphasis added) is unclear, rendering this claim indefinite. For the purposes of examination, this limitation will be interpreted as “the second interface is located on the pGaN layer where the pGaN layer has
Regarding Claim 18,
Lin. 15 – 16 recite the limitation “the second interface is located at a depth within the pGaN layer having a lower concentration of p-dopants than the first interface”. However, an interface of a layer is always located at a surface of said layer. Therefore, the meaning of the requirement “the second interface is…within the pGaN layer” (emphasis added) is unclear, rendering this claim indefinite. For the purposes of examination, this limitation will be interpreted as “the second interface is located on the pGaN layer where the pGaN layer has
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 1 – 6 & 16 – 19 are rejected under 35 U.S.C. 103 as being unpatentable over OH (US 20210336045 A1) in view of OKAWA (US 20160380091 A1).
Regarding Claim 1,
OH discloses:
A field effect transistor (FET) device (Fig. 22: 600), comprising:
a substrate (Fig. 23: 110);
a gallium nitride (GaN) structure (Fig. 25: 120/130/640s; Par. 130) covering a portion of the substrate;
a gate metal layer (Fig. 25: 650/660; Par. 131 & Fig. 2: 150/160; Par. 84 – 88, where 650/660 & 150/160 comprise the same materials, respectively; Par. 107 & 111) on top of the GaN structure;
wherein the GaN structure comprises:
at least one first section (Fig. 25: 640 under horizontal 640/650 interface) having a first height, and
a second section (Fig. 25: 640 under horizontal 640/660 interface) having a second height that is smaller than the first height;
wherein a first interface (Fig. 25: 640/650 interface) between the at least one first section of the GaN structure and the gate metal layer has ohmic contact properties (Par. 131);
wherein a second interface (Fig. 25: 640/660 interface) between the second section of the GaN structure and the gate metal layer has non-ohmic contact properties (Par. 132);
wherein the GaN structure comprises a p-doped GaN (pGaN) layer (Fig 25: 640; Par. 130);
OH does not disclose:
wherein a concentration of p-dopants in the pGaN layer decreases as a function of depth from the first interface; and
wherein the second interface is located on the pGaN layer where the pGaN layer has a lower concentration of p-dopants than the first interface.
OKAWA discloses:
wherein a concentration of p-dopants (As seen in Fig. 9) in the pGaN layer (Fig. 9: 34; Par. 33 & 51) decreases as a function of depth from the first interface (Fig. 9: 38a); and
(Note, while the concentration of p-dopants in 34 is illustrated to discontinuously decrease—at the interface between 34a and 34b—as a function of depth from 38a, a discontinuous function of depth may be construed as a function of depth under a broadest reasonable interpretation, thereby satisfying this limitation.)
wherein the second interface (Fig. 9: 37a) is located on the pGaN layer (34) where the pGaN layer (34) has a lower concentration of p-dopants (As seen in Fig. 9) than the first interface (38a).
Further, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of OH with those of OKAWA such that the first interface is more heavily doped with p-type dopants than the second interface to enable a concentration of p-dopants in the pGaN layer to decrease as a function of depth from the first interface and the second interface to be located on the pGaN layer where the pGaN layer has a lower concentration of p-dopants than the first interface in OH according to the teachings of OKAWA for the further advantage of suppressing undesirable gate-leakage current (OKAWA Par. 51). Further still, a higher concentration of p-dopants in the pGaN layer below the first interface is known in the art to improve the ohmic characteristics of said first interface
Regarding Claim 2,
OH discloses:
The FET device of claim1,
wherein the first interface forms an ohmic contact (Par. 131), and/or
wherein the second interface forms a Schottky junction (Par. 132).
Regarding Claim 3,
OH does not disclose:
The FET device of claim 1,
wherein 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 does disclose simulated data (Fig. 4; Par. 94) providing the relationship between gate leakage current and the percentage the second interface—and, thus, the first interface—makes up of the total interface area between the GaN structure and the gate metal layer, the total interface area comprising the first interface and the second interface.
Further, this data is provided for the scenario where the first interface makes up 7% (Fig. 4: 93% trendline) of the total interface area between the GaN structure and the gate metal layer, the total interface area comprising the first interface and the second interface.
As such, OH recognizes the percentage the first interface makes up of the total interface area between the GaN structure and the gate metal layer, the total interface area comprising the first interface and the second interface, is a result effective variable, as said percentage provides a means to balance the amount of gate leakage current and turn-on resistance reduction (OH Par. 97). Further, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to select a value of said percentage in OH to fall within the claimed range as a means to strike a desired balance between gate current leakage and turn-on resistance reduction.
Regarding Claim 4,
OH discloses:
The FET device of claim 1,
wherein the GaN structure comprises a plurality of first sections that are separated from each other (As seen in Fig. 25).
Regarding Claim 5,
OH discloses:
The FET device of claim 1,
wherein a separating layer (Fig. 25: 660) is arranged around the first interface on the GaN structure to physically separate the first interface from the second interface (As seen in Fig. 22, 23, & 25).
Regarding Claim 6,
OH discloses:
The FET device of claim 1,
wherein the GaN structure comprises a sloped transition region from the first section to the second section.
(Fig. 25: the GaN structure comprises a vertically sloped and instantaneous transition region from the first section to the second section.)
Regarding Claim 16,
OH discloses:
The FET device of claim 1,
wherein the gate metal layer is formed by a metal stack (As seen in Fig. 25),
OH does not disclose:
wherein the 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/AI/TiN.
OKAWA discloses:
wherein the metal stack (Fig. 9: 37/38) 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/AI/TiN (Par. 35: 38 may comprise Pt, Pb, or an alloy thereof & Par. 36: 37 may comprise Ni, W, Ti, Al, or an alloy thereof).
Further, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of OH with those of OKAWA to enable the metal stack to comprise Ti/Al or Ti/Al/Ti in OH according to the teachings of OKAWA, as one of ordinary skill in the art would have recognized the finite number of predictable material combinations for the metal stack. As such, absent unexpected results, it would have been obvious to one of ordinary skill in the art to try said material combinations in order to determine which yields the best device functionality.
Regarding Claim 17,
OH discloses:
The FET device of claim 1,
wherein the FET device is a GaN-gate high electron mobility transistor (HEMT) device (Par. 71).
Regarding Claim 18,
OH discloses:
Method of fabricating a field effect transistor (FET) device (Fig. 5 – 8), comprising the steps of:
providing a substrate (Fig. 5: 110);
forming a gallium nitride (GaN) structure (Fig. 5 – 6: 140; Par. 82) on top of the substrate,
wherein the GaN structure comprises at least one first section (Fig. 7: section of 140 under 150) having a first height, and a second section (Fig. 7: section of 140 not under 150) having a second height that is smaller than the first height;
forming a gate metal layer (Fig. 7 – 8: 150/160; Par. 84 – 88) on top of the GaN structure;
wherein a first interface (Fig. 8: 140/150 interface) between the at least one first section of the GaN structure and the gate metal layer has ohmic contact properties (Par. 85),
wherein a second interface (Fig. 8: 140/160 interface) between the second section of the GaN structure and the gate metal layer has non-ohmic contact properties (Par. 87);
wherein the GaN structure comprises a p-doped GaN (pGaN) layer (Fig 8: 140; Par. 82);
OH does not disclose:
wherein a concentration of p-dopants in the pGaN layer decreases as a function of depth from the first interface; and
wherein the second interface is located on the pGaN layer where the pGaN layer has a lower concentration of p-dopants than the first interface.
OKAWA discloses:
wherein a concentration of p-dopants (As seen in Fig. 9) in the pGaN layer (Fig. 9: 34; Par. 33 & 51) decreases as a function of depth from the first interface (Fig. 9: 38a); and
(Note, while the concentration of p-dopants in 34 is illustrated to discontinuously decrease—at the interface between 34a and 34b—as a function of depth from 38a, a discontinuous function of depth may be construed as a function of depth under a broadest reasonable interpretation, thereby satisfying this limitation.)
wherein the second interface (Fig. 9: 37a) is located on the pGaN layer (34) where the pGaN layer (34) has a lower concentration of p-dopants (As seen in Fig. 9) than the first interface (38a).
Further, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teachings of OH with those of OKAWA such that the first interface is more heavily doped with p-type dopants than the second interface to enable a concentration of p-dopants in the pGaN layer to decrease as a function of depth from the first interface and the second interface to be located on the pGaN layer where the pGaN layer has a lower concentration of p-dopants than the first interface in OH according to the teachings of OKAWA for the further advantage of suppressing undesirable gate-leakage current (OKAWA Par. 51). Further still, a higher concentration of p-dopants in the pGaN layer below the first interface is known in the art to improve the ohmic characteristics of said first interface
Regarding Claim 19,
OH discloses:
The method of claim 18,
wherein the GaN structure comprises a p-doped GaN, pGaN, layer (Fig 2: 140; Par. 82);
OH does not disclose:
wherein a concentration of p-dopants in the pGaN layer is higher in a region below the first interface than in a region below the second interface.
OKAWA discloses:
wherein a concentration of p-dopants (As seen in Fig. 9) in the pGaN layer (Fig. 9: 34; Par. 33 & 51) is higher in a region (Fig. 9: 34a) below the first interface (Fig. 9: 38a) than in a region (Fig. 9: 34b) below the second interface (Fig. 9: 37a).
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Kenneth S. Stephenson whose telephone number is (571)272-6686. The examiner can normally be reached Monday through Friday, 9 A.M. to 5 P.M. (EST)..
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Julio Maldonado can be reached at (571) 272-1864. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/K.S.S./Examiner, Art Unit 2898
/JULIO J MALDONADO/Supervisory Patent Examiner, Art Unit 2898
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