Prosecution Insights
Last updated: April 19, 2026
Application No. 18/174,462

HEMT DEVICE AND MANUFACTURING PROCESS THEREOF

Non-Final OA §102§103
Filed
Feb 24, 2023
Examiner
AHMAD, KHAJA
Art Unit
2813
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
STMicroelectronics
OA Round
1 (Non-Final)
81%
Grant Probability
Favorable
1-2
OA Rounds
2y 5m
To Grant
99%
With Interview

Examiner Intelligence

Grants 81% — above average
81%
Career Allow Rate
750 granted / 928 resolved
+12.8% vs TC avg
Strong +27% interview lift
Without
With
+26.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 5m
Avg Prosecution
36 currently pending
Career history
964
Total Applications
across all art units

Statute-Specific Performance

§101
1.3%
-38.7% vs TC avg
§103
58.3%
+18.3% vs TC avg
§102
28.7%
-11.3% vs TC avg
§112
5.3%
-34.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 928 resolved cases

Office Action

§102 §103
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 Applicant Election filled on 11/11/2025. Currently, claims 10-29 are pending in the application. Claims 1-9 have been withdrawn and cancelled from consideration. Claims 21-29 have been added new. Election/Restrictions Applicant's election without traverse of Group II, claims 10-29, in the reply filed on 11/11/2025 is acknowledged, there being no allowable generic or linking claim. Claim Rejections - 35 USC § 102 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 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 10-14, 17, 21-25 and 29 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by LEI et al (US 20220140096 A1). Regarding claim 10, Figure 2 of LEI discloses a process for manufacturing a HTEMT device ([0002]), comprising: forming a source region (106, [0028]) and a drain region (108, [0028]) each extending into a heterostructure (104+114, [0002] and [0029]); forming, on the heterostructure, an insulation layer (116, [0031]) having a thickness along a first direction (vertical direction in the Figure 2) and covering the source region (106) and the drain region (108); and forming a gate region (recess region in 114 and 116 in Figure 2B, [0033]), wherein the gate region includes a first portion (top portion) extending through the insulation layer (116), throughout the thickness of the insulation layer (116), and having a first width along a second direction (horizontal direction in the Figure 2) transverse to the first direction, and a second portion (bottom portion of gate region) extending in the heterostructure (104+114) and having a second width along the second direction, the second width being different from the first width (the width of the trench in 114 is different from the width in 116). Regarding claim 11, Figure 2 of LEI discloses that the manufacturing process according to claim 10, wherein forming the gate region includes: forming a window (trench in Figure 2B) in the insulation layer (116); forming a recess (opening in 114) in the heterostructure, at the window; and depositing at least one conductive layer (110, [0033]) in the window. Regarding claim 12, Figure 2 of LEI discloses that the manufacturing process according to claim 10, wherein the heterostructure includes a channel layer (104) and a barrier layer (114) on the channel layer, the insulation layer (116) being positioned on the barrier layer, the second portion (bottom region of 110) of the gate region extending in the barrier layer (114). Regarding claim 13, Figure 2 of LEI discloses that the manufacturing process according to claim 12, wherein the second portion (bottom portion) of the gate region (recess shown in the Figure 2B) extends partially through the barrier layer (114, [0033]) and ends in the barrier layer. Regarding claim 14, Figure 2 of LEI discloses that the manufacturing process according to claim 12, wherein the width of the first portion (lower portion in 114) of the gate region (recess region in 114and 116) is greater than the width of the second portion (upper portion in 116) of the gate region. Regarding claim 17, Figure 2 of LEI discloses a method, comprising: forming a heterostructure (104+114, [0030]) of an HEMT device ([0003]); forming a source region (106, [0028]) and a drain region (108, [0028]) extending into the heterostructure; depositing an insulating layer (204/116, [0038]) on the heterostructure and over the source region and the drain region; patterning an opening (in Figure2B) in the insulating layer (116) between the source region and the drain region and exposing the heterostructure (opening in 116 exposing 114); forming, through the opening in the insulating layer, a trench (bottom portion of the opening in 114 is the trench) in the heterostructure, the trench (opening in 114) having a width smaller than a width of the opening (width of the opening in 116); and forming a gate electrode (110, [0034]) having a first portion in the trench in the heterostructure, a second portion in the opening in the insulating layer, and a third portion (part of 110 on 112 in Figure2D) on a top surface of the insulating layer (116). Regarding claim 21, Figure 2 of LEI discloses a method of forming an HEMT device, comprising: forming a channel layer (104, [0029] and [0052]); forming a barrier layer (114, [0029]) on the channel layer; forming a source region (106, [0028]) extending through the barrier layer; forming a drain region (108, [0028]) extending into the barrier layer; forming a trench (in 114, Figure 2B) in the barrier layer between the source region and the drain region; forming a gate region (opening in Figure 2B) including a first portion (top portion of the opening in 116 in the Figure 2B) on a top surface of the barrier layer and having a first width in a first direction (horizontal direction in the Figure 2) and a second portion (bottom portion of the opening in 114) in the trench and having a second width along the first direction, the second width being different from the first width. Regarding claim 22, Figure 2 of LEI discloses that the method of claim 21, further comprising forming an insulation layer (116, [0031]) on the barrier layer (114, [0030]) prior to forming the trench and having a thickness (vertical thickness of 114) along a second direction and covering the source region (106) and the drain region (108). Regarding claim 23, Figure 2 of LEI discloses that the method of claim 22, wherein the first portion (top portion of the opening in 116 in the Figure 2B) of the gate region is surrounded by the insulation layer (116, [0031]). Regarding claim 24, Figure 2 of LEI discloses that the method of claim 23, wherein the second portion (bottom portion of the opening in 114) of the gate region extends partially through the barrier layer (114, [0029]) and ends in the barrier layer. Regarding claim 25, Figure 2 of LEI discloses that the method of claim 23, wherein the width of the first portion of the gate region is greater than the width of the second portion of the gate region (top portion of opening in 116 is greater than the bottom portion of the opening in 114). Regarding claim 29, Figure 2 of LEI discloses that the method of claim 23, wherein the gate region includes an insulating layer (112, [0028]) and a conductive layer (110, [0030]), the insulating layer extending between the heterostructure and the conductive layer. 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 15-16, 18-20 and 26-28 are rejected under 35 U.S.C. 103 as being obvious over LEI et al (US 20220140096 A1) in view of Sheppard et al (US 20130252386 A1). Regarding claims 15-16, 20 and 26-28, Figure 2 of LEI does not teach that the manufacturing process according to claim 12, wherein the barrier layer includes a first barrier portion of a first material and a second barrier portion of a second material different from the first material, the first barrier portion extending between the channel layer and the second barrier portion, wherein the second portion of the gate region extends in the second barrier portion up to an interface between the first barrier portion and the second barrier portion. Or The method of claim 17, wherein the heterostructure includes a channel layer and a barrier layer on the channel layer, the barrier layer having a first sub-layer and a second sub-layer, wherein forming the trench includes etching through the second sub-layer and utilizing the first sub-layer as an etch-stop. Or The method of claim 23, wherein the barrier layer includes a first barrier portion of a first material and a second barrier portion of a second material different from the first material, the first barrier portion extending between the channel layer and the second barrier portion, wherein the second portion of the gate region extends in the second barrier portion up to an interface between the first barrier portion and the second barrier portion. Or The method of claim 23, wherein the gate region includes conductive material in direct electrical contact with the barrier layer. However, Sheppard is a pertinent art which teaches semiconductor devices and in particular relates to transistors, such as high electron mobility transistors (HEMT), that incorporate nitride-based active layers and a recessed gate structure, and methods of fabricating same. Sheppard teaches that cap layer (second barrier layer, 24 Figures 3-4) on a first barrier layer (22) to achieve high breakdown voltage and protecting the barrier layer during etching ([0010] and [0055]-[0056]). Sheppard, further, teaches that the gate (32) of the device can be in contact with the first buffer layer (22) ([0051] and [0055]). 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 method of LEI according to the teaching of Sheppard as claimed above in order to a HEMT with high breakdown voltage and schottky contact HEMT device and protecting the barrier layer from damage during fabrication ([0010]-[0011] of LEI). Regarding claims 18-19, Figure 2 of LEI does not teach that the method of claim 17, wherein forming the trench includes: forming a mask layer on the insulating layer and in the opening; patterning the mask layer to expose a portion of the heterostructure in the opening; and forming the trench by etching the exposed portion of the heterostructure, comprising forming the gate electrode after removing the mask layer. However, Sheppard is a pertinent art which teaches semiconductor devices and in particular relates to transistors, such as high electron mobility transistors (HEMT), that incorporate nitride-based active layers and a recessed gate structure, and methods of fabricating same. Figures 1A-1H of Sheppard teach of forming a mask layer (42) on dielectric layers (26/28) and patterning the mask layer to expose a portion of the heterostructure (22+20) in the opening; and forming the trench (36) by etching the exposed portion of the heterostructure, comprising forming the gate electrode (32) after removing the mask layer in method of forming the HEMT with improved method for high breakdown voltage and protecting the layers from etching ([0010]-[0011]). 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 method of LEI according to the teaching of Sheppard as claimed above in order to a HEMT with high breakdown voltage and a schottky contact HEMT device, and protecting the barrier layer from damage during fabrication ([0010]-[0011] of LEI). Examiner Notes A reference to specific paragraphs, columns, pages, or figures in a cited prior art reference is not limited to preferred embodiments or any specific examples. It is well settled that a prior art reference, in its entirety, must be considered for all that it expressly teaches and fairly suggests to one having ordinary skill in the art. Stated differently, a prior art disclosure reading on a limitation of Applicant's claim cannot be ignored on the ground that other embodiments disclosed were instead cited. Therefore, the Examiner's citation to a specific portion of a single prior art reference is not intended to exclusively dictate, but rather, to demonstrate an exemplary disclosure commensurate with the specific limitations being addressed. In re Heck, 699 F.2d 1331, 1332-33,216 USPQ 1038, 1039 (Fed. Cir. 1983) (quoting In re Lemelson, 397 F.2d 1006, 1009, 158 USPQ 275, 277 (CCPA 1968)). In re: Upsher-Smith Labs. v. Pamlab, LLC, 412 F.3d 1319, 1323, 75 USPQ2d 1213, 1215 (Fed. Cir. 2005); In re Fritch, 972 F.2d 1260, 1264, 23 USPQ2d 1780, 1782 (Fed. Cir. 1992); Merck& Co. v. BiocraftLabs., Inc., 874 F.2d 804, 807, 10 USPQ2d 1843, 1846 (Fed. Cir. 1989); In re Fracalossi, 681 F.2d 792,794 n.1, 215 USPQ 569, 570 n.1 (CCPA 1982); In re Lamberti, 545 F.2d 747, 750, 192 USPQ 278, 280 (CCPA 1976); In re Bozek, 416 F.2d 1385, 1390, 163 USPQ 545, 549 (CCPA 1969). Conclusion 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-Friday, 8:00 AM - 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. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice . Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /KHAJA AHMAD/Primary Examiner, Art Unit 2813
Read full office action

Prosecution Timeline

Feb 24, 2023
Application Filed
Dec 26, 2025
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
81%
Grant Probability
99%
With Interview (+26.9%)
2y 5m
Median Time to Grant
Low
PTA Risk
Based on 928 resolved cases by this examiner. Grant probability derived from career allow rate.

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