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 .
This Office action is in response to the amendment filed 12/30/2025 in which claims 1, 12, 13, 16, 20, and 28 were amended.
Claims 1-30 are pending with claims 1-5, 7-13, and 16-18 presented for examination and claims 6, 14, 15, and 19-30 remaining withdrawn.
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.
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 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Sheppard et al (US 2011/0057232 and Sheppard hereinafter) in view of Hirai et al (US 2016/0260615 and Hirai hereinafter).
As to claims 1 and 10: Sheppard discloses [claim 1] a transistor device (Fig. 1D; [0043]), comprising: a semiconductor structure (comprising 20, 22, and 31; [0050]-[0052] and [0067]) comprising an implanted region (31) adjacent a surface (top surface of 22) thereof; and a source/drain contact (30; [0083]-[0084]) comprising an ohmic contact portion (30 in contact with 31; [0084]) on the implanted region (31) of the semiconductor structure (comprising 20, 22, and 31), wherein the implanted region (31) laterally extends beyond the ohmic contact portion (30 in contact with 31) by less than about 0.8 microns (distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31, can be about 0.1 to about 0.5 microns, in particular 0.25 microns; [0084]); [claim 10] wherein: an electrical conduction path (inherently present during device operation) between a channel region (Fig. 1D; region under dielectric 24; [0076]) of the semiconductor structure (comprising 20, 22, and 31) and the source/drain contact (30) comprises a first resistance (inherently there is a resistance in the materials when there is an electrical conduction path) between the semiconductor structure (comprising 20, 22, and 31) and a boundary (outer edge) of the implanted region (31), and a second resistance (inherently there is a resistance in the materials when there is an electrical conduction path) between the implanted region (31) and the ohmic contact portion (30).
Sheppard fails to expressly disclose where [claim 1] the source/drain contact laterally extends beyond the implanted region.
Sheppard shows a square/rectangular cross-section for the source/drain contact 30.
Hirai shows in Fig. 1 where the source/drain contacts SE/DE can have a “T”-shaped structure. The “T”-shaped structure of the SE can extend over an isolation region adjacent the source region and can extend over the gate electrode. The “T”-shaped structure of the DE can extend over the isolation region adjacent the drain region. When the “T” shaped SE/DE structures and isolation region of Hirai are modified into Sheppard, the isolation region ISO of Hirai would abut the outer edges of the implanted regions 31 and the “T”-shaped SE/DE structures would have their outer portions overlying the isolation structures such that they extend beyond the implanted region. Further, the “T”-shaped SE would have a field plate extension that extends beyond the implanted region and over the gate electrode.
Therefore, given the teachings of Hirai, 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 Sheppard by employing the well-known or conventional features of HEMT fabrication, such as displayed by Hirai, by employing an isolation region around a HEMT in order to electrically isolate the HEMT from other devices on the substrate and by employing "T" shaped source/drain contacts, such that .
As to where [claim 10] the implanted region is substantially free of a third resistance between the boundary of thereof and an edge of the ohmic contact portion, Sheppard discloses that the implanted regions are doped to a desired concentration, see [0069]. The doping energy and dose are chosen to lower the resistance of the implanted region and to permit fabrication of low resistivity ohmic contacts to the doped region, see [0070].
As Sheppard recognizes that the doping energy and dose are result effective variables, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Sheppard’s dosage and energy of the implanted region such that the resistance of the implanted region 30 is lowered as much as possible (to “substantially” zero). One would have chosen the dosage and energy according to a result effective variable desire to reduce the resistance of the implanted region and the contact resistance within the implanted region.
As to claims 2 and 3: Sheppard in view of Hirai fail to expressly disclose [claim 2] wherein the implanted region laterally extends less than about 0.2 microns from an edge of the ohmic contact portion; [claim 3] wherein the implanted region laterally extends beyond an edge of the ohmic contact portion by less than about 0.1 microns.
Sheppard discloses in [0084] that the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31, can be about 0.1 to about 0.5 microns.
As stated in MPEP 2144.05(I), “[i]n the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists.”
Sheppard discloses that the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31 is set to allow for misalignment tolerances in the formation and patterning of the ohmic metal contact 30 to prevent the metal in 30 from diffusing into dielectric layer 24, whereby a short between the gate contact and the ohmic contacts is prevented ([0084]).
Therefore, a person having ordinary skill in the art before the effective filing date of the claimed invention to set the distance between the ohmic contacts and the dielectric layer, which is the same distance by which the implanted region 31 extends beyond the edge of the ohmic contact 30, by less than about 0.2 microns and by less than about 0.1 microns, since the claimed ranges and the disclosed range overlap and doing so would involve only routine experimentation, in order to prevent a short between the gate contact and the ohmic contacts while minimizing a distance between the structures ([0084]).
As to claim 4: Sheppard in view of Hirai fail to expressly disclose wherein the implanted region laterally extends beyond an edge of the ohmic contact portion by less than about 0.05 microns.
Sheppard discloses in [0084] that the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31, can be about 0.1 to about 0.5 microns. Sheppard discloses that the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31 is set to allow for misalignment tolerances in the formation and patterning of the ohmic metal contact 30 to prevent the metal in 30 from diffusing into dielectric layer 24, whereby a short between the gate contact and the ohmic contacts is prevented ([0084]). Thus, Sheppard establishes that the distance is a result effective variable.
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to set the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31, to less than about 0.05 microns for the purpose of preventing a short between the gate contact and the ohmic contacts by allowing for misalignment tolerances in formation and patterning of the ohmic metal contact while minimizing the size of the device to allow for more devices to be constructed on the same substrate. As stated in MPEP 2144.05(I), a prima facie case of obviousness exists where the claimed range and the prior art range do not overlap but are close enough that one skilled in the art would have expected them to have the same properties (Titanium Metals Corp. v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985)).
Further, as Sheppard recognizes that the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31,is a result effective variable, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Sheppard’s distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31 to have a distance less than about 0.05 microns, which is slightly smaller than the prior art range of about 0.1 microns. One would have chosen the distance between the closest edge of 30 to 24 and the closest edge of 24 to 30, which corresponds to the part of 31 laterally extending beyond the edge of 30 in contact with 31 according to a result effective variable balancing the need to prevent the ohmic contact and the dielectric from touching but not be so large to defeat the protective purpose of the dielectric layer ([0084]).
As to claim 5: Sheppard in view of Hirai fail to expressly disclose wherein an electrical resistance of a lateral extension of the implanted region beyond an edge of the ohmic contact portion is substantially zero.
Sheppard discloses that the implanted regions are doped to a desired concentration, see [0069]. The doping energy and dose are chosen to lower the resistance of the implanted region and to permit fabrication of low resistivity ohmic contacts to the doped region, see [0070].
As Sheppard recognizes that the doping energy and dose are result effective variables, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Sheppard’s dosage and energy of the implanted region such that the resistance of the implanted region 30 is lowered as much as possible (to “substantially” zero). One would have chosen the dosage and energy according to a result effective variable desire to reduce the resistance of the implanted region and the contact resistance within the implanted region.
Claims 7 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Sheppard in view of Hirai as applied to claim 1 above, and further in view of Sun et al (US 2021/0384339 and Sun hereinafter).
As to claims 7 and 8: Sheppard combined with Hirai discloses wherein the semiconductor structure (Fig. 1D; comprising 20, 22, and 31) comprises a channel layer (20) and a barrier layer (22) thereon.
Sheppard in view of Hirai discloses [claim 8] wherein the source/drain contact (Fig. 1; SE/DE; [0059]) further comprises an extension portion (portion of SE/DE on top surface of IL) on the barrier layer (BA; [0055]).
As to [claim 8] where the extension portion is laterally extending beyond a boundary of the implanted region, When the “T” shaped SE/DE structures and isolation region of Hirai are modified into Sheppard, the isolation region ISO of Hirai would abut the outer edges of the implanted regions 31 and the “T”-shaped SE/DE structures would have their outer portions overlying the isolation structures such that they extend beyond the implanted region. Further, the “T”-shaped SE would have a field plate extension that extends beyond the implanted region and over the gate electrode.
Therefore, given the teachings of Hirai, 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 Sheppard by employing the well-known or conventional features of HEMT fabrication, such as displayed by Hirai, by employing "T"-shaped source/drain contacts, such that the contacts have a portion that extend laterally beyond the source/drain (implanted) regions and the source contact extends laterally beyond the implanted region and over the gate electrode in order to improve the breakdown voltage of the device ([0060]).
Sheppard in view of Hirai fail to expressly disclose [claim 7] wherein the ohmic contact portion of the source/drain contact extends into a recess in the barrier layer; [claim 8] where the extension region on the barrier layer is outside the recess.
Sun discloses a HEMT [claim 7] wherein the ohmic contact portion (Fig. 12; source/drain ohmic contact within the trench of the upper barrier layer and etching transition layer; [0102]) of the source/drain contact (source/drain ohmic contact) extends into a recess (trench within the upper barrier layer; [0098]) in the barrier layer (comprising the upper barrier layer, the etching transition layer, and the lower barrier layer; [0096]-[0097]); [claim 8] wherein the source/drain contact (Fig. 12; source/drain ohmic contact) further comprises an extension portion (horizontal portion of source/drain contact on a topmost surface of the gate dielectric) on the barrier layer (comprising the upper barrier layer, the etching transition layer, and the lower barrier layer) outside the recess (trench within upper barrier layer and etching transition layer).
Therefore, given the teachings of Sun, 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 Sheppard in view of Hirai by employing the well-known or conventional features of HEMT fabrication, such as displayed by Sun, by employing "T"-shaped source/drain contacts that have an ohmic contact portion that extend into a recess of the barrier layer in order to improve the electrical characteristics of the device ([0084] and [0114])..
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Sheppard in view of Hirai as applied to claim 1 above, and further in view of Makiyama et al (US 2009/0085063 and Makiyama hereinafter) in view of Taniguchi et al (US 2021/0111277 and Taniguchi hereinafter).
Although the structure disclosed by Sheppard in view of Hirai shows substantial features of the claimed invention (discussed in paragraph 8 above), it fails to expressly disclose:
wherein a lateral distance between the source/drain contact and an adjacent source/drain contact is about 3 microns or less, and an on- resistance of the transistor device is less than about 1.7 ohm-millimeters.
Makiyama discloses a HEMT where a lateral distance between the source contact and the drain contact (the source/drain contact and an adjacent source/drain contact) is about 2 microns, see [0050] and [0073].
Taniguchi discloses a HEMT with an on-resistance of 0.4 ohm-mm, see [0124].
Therefore, a person having ordinary skill in the art before the effective filing date of the claimed invention could have combined all the elements as claimed as all the claimed elements were known in the prior art with no change in their respective functions and the combination would have yielded predictable results, namely employing a contact structure to an implanted region where the distance between the source and drain contacts is within the claimed range such that an on-resistance within the claimed range is provided in order to suppress distortion in a signal ([0011] of Taniguchi) and to provide a HEMT with improved electrical characteristics ([0073] of Makiyama).
Allowable Subject Matter
Claim 9 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.
Claims 12, 13, and 16-18 are allowed over the prior art of record. Examiner notes that rejoinder is not considered until the case is allowed in its entirety.
The following is a statement of reasons for the indication of allowable subject matter:
As to claim 12: the closest prior art, Sheppard, discloses a transistor device (Fig. 1D; [0043]), comprising: a semiconductor structure (comprising 20, 22, and 31; [0050]-[0052] and [0067]) comprising a contact region (31) adjacent a surface (top surface of 22) thereof; and a source/drain contact (30; [0083]-[0084]) comprising an ohmic contact portion (30 in contact with 31; [0084]) on the contact region (31) of the semiconductor structure (comprising 20, 22, and 31), a lateral extension (portion of 31 not underneath 30) of the contact region (31) beyond an edge of the ohmic contact portion (30); wherein an electrical conduction path (inherently present during device operation) between a channel region (Fig. 1D; region under dielectric 24; [0076]) of the semiconductor structure (comprising 20, 22, and 31) and the source/drain contact (30) comprises a first resistance (inherently there is a resistance in the materials when there is an electrical conduction path) between the semiconductor structure (comprising 20, 22, and 31) and a boundary (edge) of the contact region (31), a second resistance (inherently there is a resistance in the materials when there is an electrical conduction path) between the contact region (31) and the ohmic contact portion (30), and a third resistance (inherently there is a resistance in the doped region of the implanted region 31 in its entirety) of a lateral extension of the contact region (31) between the boundary (edge) and an edge (right side) of the ohmic contact portion (30). Sheppard fails to expressly disclose where the third resistance is less than the second resistance.
As to claim 16: the closest prior art, Sheppard, discloses a transistor device (Fig. 1D; [0043]), comprising: a semiconductor structure (comprising 20, 22, and 31; [0050]-[0052] and [0067]) comprising implanted regions (31) adjacent a surface (top surface of 22) thereof; and source/drain contacts (30; [0083]-[0084]) comprising ohmic contact portions (portions of 30 in direct contact with 31) on the implanted regions (31) of the semiconductor structure (comprising 20, 22, and 31), respectively. Sheppard fails to expressly disclose wherein a lateral distance between the source and drain contacts is about 3 microns or less, an on-resistance of the transistor device is less than about 1.7 ohm-millimeters, and the on-resistance includes a resistance of a lateral extension of the implanted regions beyond the ohmic contact portions.
Response to Arguments
Applicant's arguments filed 12/30/2025 have been fully considered but they are not persuasive.
In the remarks, applicant argues in substance that: in regards to claim 1, Sheppard does not disclose or suggest that the source/drain contact laterally extends beyond the implanted region. The fabrication method of Sheppard specifically requires that the source/drain contact does not laterally extend beyond the implanted region. Nor would it be obvious to modify Sheppard to include such lateral extension of the source/drain contact based on the teachings of the remaining cited references or otherwise as Sheppard teaches away from having the source/drain contact extend beyond the implanted region to avoid a short with the gate contact.
Examiner respectfully traverses applicant’s remarks. Sheppard does not teach away from nor requires that the source/drain contact not extend beyond the implanted region. Sheppard only requires that the source/drain contact not come into contact with the dielectric layer 24. To teach away, there must be some statement stating that to perform some step or provide some feature is undesirable or would break the device. Hirai provides a T-shaped source/drain contact that extends laterally beyond the implanted region of Sheppard and over an included isolation region and a source contact that extends beyond the implanted region and over the gate electrode. The “T” shaped structure, specifically the line portion that would be included into Sheppard from Hirai, would not come into contact with the dielectric 24 as required by Sheppard. Hirai further provides a motivation for providing the “T”-shaped structures, see the rejection above in paragraph 8.
Applicant’s arguments, see pages 14-16, filed 12/30/2025, with respect to the combination of Sheppard, Makiyama, and Taniguchi have been fully considered and are persuasive. The rejection of claims 16-18 on 9/30/2025 has been withdrawn.
Specifically, Examiner agrees that while the disparate values of the source-to-drain distance of 3 microns and the on-resistance of the transistor of 1.7 ohm-mm, there is no specific teaching as to how one of ordinary skill in the art before the effective filing date of the claimed invention would achieve those values while balancing the lateral extension of the implanted regions beyond the ohmic contact portions need. The values taught by Makiyama for the distance and Taniguchi for the on-resistance are provided without a nexus in terms of teaching how to achieve all three without undue experimentation as there is no teaching of a relationship between the three requirements that can be optimized or modified.
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 JOSEPH C NICELY whose telephone number is (571)270-3834. The examiner can normally be reached Monday-Friday 7:30 am - 4 pm, EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Steven Gauthier can be reached at (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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JOSEPH C. NICELY
Primary Examiner
Art Unit 2813
/JOSEPH C. NICELY/Primary Examiner, Art Unit 2813
4/7/2026
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