Prosecution Insights
Last updated: April 19, 2026
Application No. 18/526,532

TRIAC DEVICE WITH HIGH COMMUTATING CAPABILITY

Non-Final OA §103§112
Filed
Dec 01, 2023
Examiner
LINDSEY, COLE LEON
Art Unit
2812
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Littelfuse Semiconductor (Wuxi) Co. Ltd.
OA Round
1 (Non-Final)
89%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 89% — above average
89%
Career Allow Rate
103 granted / 116 resolved
+20.8% vs TC avg
Moderate +13% lift
Without
With
+12.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
34 currently pending
Career history
150
Total Applications
across all art units

Statute-Specific Performance

§103
55.8%
+15.8% vs TC avg
§102
27.2%
-12.8% vs TC avg
§112
15.1%
-24.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 116 resolved cases

Office Action

§103 §112
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 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. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-5 and 7-20 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claims 1 and 20 each of the claims recites the limitation “one or more silicon regions in the first silicon layer and in the third silicon layer.” As the first and third silicon layers as claimed could also be defined as silicon regions, it is not immediately clear to a person of ordinary skill in the art the distinction between silicon layers and silicon regions within those silicon layers as claimed. In the interest of compact prosecution, and par. 53 of the specification, examiner will interpret the limitation to mean “one or more doped silicon regions in the first silicon layer and in the third silicon layer.” Examiner notes that claim 6 defines the one or more silicon regions as n-type regions which clarifies the indefinite issue, and additionally notes that while claim 21 recites a similar limitation, as it is for a method, the method of forming one or more regions within a layer does not suffer the same indefinite issue as with the device claims. Claims 2-5 and 7-19 are rejected under 35 U.S.C. 112(b) as being dependent upon a claim rejected under 35 U.S.C. 112(b). 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 1-21 are rejected under 35 U.S.C. 103 as being unpatentable over Hutson (US4021837A) in view of Galtie et al. (US20020008247A1, hereinafter Galtie). Regarding claim 1, Hutson teaches an apparatus, comprising: a first silicon layer (Fig. 4 layer 14), a second silicon layer (Fig. 4 layer 12), and a third silicon layer (Fig. 4 layer 16), the first silicon being coupled to the second silicon layer and the second silicon layer being coupled to the third silicon layer (Fig. 4 layers 12/14/16 all coupled to each other); a trench formed in the first silicon layer and in at least a portion of the second silicon layer (Fig. 4 grooves 92/94 formed in layers 14/16 and extending into layer 12 from both directions); an isolation region formed in at least the second silicon layer (Fig. 4 carrier lifetime degrading material 96/98 in grooves 92/94); a first main terminal one and a first gate terminal coupled to a first portion of the first silicon layer (Fig. 4 electrodes 30 and 24 coupled to a portion of layer 14 to the left of groove 92); a second main terminal one and a second gate terminal coupled to a second portion of the first silicon layer (Fig. 4 electrodes 32 and 26 coupled to a portion of layer 14 to the right of groove 92); a main terminal two coupled to the third silicon layer (Fig. 4 electrode 38 coupled to layer 16); and one or more silicon regions in the first silicon layer and in the third silicon layer (Fig. 4 N+ type layers 16/18 in layer 14 and N+ layer 22 within layer 16). Hutson does not appear to teach wherein the isolation region is configured to extend from the trench to the third silicon layer. Galtie teaches wherein the isolation region is configured to extend from the trench to the third silicon layer (Fig. 2 p-type isolating wall 13 extends from a top surface down to a bottom surface). Being in analogous arts, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Hutson with the teachings of Galtie because as both Hutson and Galtie teach suitable and compatible methods for forming an isolating structure in a TRIAC device, it would have been obvious to combine Hutson’s trench filled with a carrier lifetime degrading material that extends partially through the center of the device with Galtie’s p-type isolating wall that extends fully through the center of the device to achieve the predictable result of forming a p-type isolating structure that extends fully through the device in combination with a trench filled with a carrier lifetime degrading material that extends partially through the center of the device. Regarding claim 2, the combination of Hutson and Galtie teaches the apparatus according to claim 1, wherein at least one of the first, second and third silicon layers is at least one of the following: an n-type layer, a p-type layer, and any combination thereof (Fig. 4 layer 14 is a p-type layer, layer 12 is an n-type layer, and layer 16 is a p-type layer). Regarding claim 3, the combination of Hutson and Galtie teaches the apparatus according to claim 2, wherein the first silicon layer and the third silicon layers are p-type layers, and the second silicon layer is an n-type layer (Fig. 4 layer 14 is a p-type layer, layer 12 is an n-type layer, and layer 16 is a p-type layer). Regarding claim 4, the combination of Hutson and Galtie teaches the apparatus according to claim 3, wherein the first and third silicon layers are P+ layers (Fig. 4 layer 14 is a p-type layer and layer 16 is a p-type layer. While the combination of Hutson and Galtie does not explicitly disclose layers 14 and 16 being p+, as the only difference between the combination of Hutson and Galtie and the claimed invention is a relative recitation of concentration in layers 14 and 16 and nothing within the disclosure indicates that a device having the claimed dimensions would perform differently than the combination of Hutson and Galtie, such a recitation of relative dimensions is not enough to be patentably distinct, see MPEP 2144.04(IV)(A)). Regarding claim 5, the combination of Hutson and Galtie teaches the apparatus according to claim 4, wherein the second silicon layer is a N- layer (Fig. 4 layer 12 is an n-type layer. While the combination of Hutson and Galtie does not explicitly disclose layers 12 as being n-, as the only difference between the combination of Hutson and Galtie and the claimed invention is a relative recitation of concentration in layer 12 and nothing within the disclosure indicates that a device having the claimed dimensions would perform differently than the combination of Hutson and Galtie, such a recitation of relative dimensions is not enough to be patentably distinct, see MPEP 2144.04(IV)(A)). Regarding claim 6, the combination of Hutson and Galtie teaches the apparatus according to claim 5, wherein the one or more silicon regions are n-type regions (Fig. 4 N+ type layers 16/18 in layer 14 and N+ layer 22 within layer 16 are n-type regions). Regarding claim 7, the combination of Hutson and Galtie teaches the apparatus according to claim 1, wherein the isolation region is a p-doped region (Galtie teaches a p-type isolating wall 13 as seen in Galtie fig. 2, see above rejection of claim 1). Regarding claim 8, the combination of Hutson and Galtie teaches the apparatus according to claim 1, wherein the trench is configured to separate the first silicon layer into the first portion of the first silicon layer and the second portion of the first silicon layer (Hutson col. 5 “[a] groove is formed in each of the outer layers to electrically separate each of the outer layers into two areas”). Regarding claim 9, the combination of Hutson and Galtie teaches the apparatus according to claim 8, wherein the trench and the isolation region are configured to separate the apparatus into a first apparatus portion and a second apparatus portion (See above rejection of claim 1, the combination of Hutson and Galtie teaches a trench isolation method and a p-type isolation region which separate the apparatus into two portions). Regarding claim 10, the combination of Hutson and Galtie teaches the apparatus according to claim 9, wherein the first main terminal one and the first gate terminal are each coupled to at least one region in the one or more regions (Hutson fig. 4 electrodes 30 coupled to N+ regions 16. While electrode 24 is not coupled to an N+ region within layer 14, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further add an N+ region below electrode 24 in order to increase contact efficiency). Regarding claim 11, the combination of Hutson and Galtie teaches the apparatus according to claim 10, wherein the second gate terminal is coupled to at least another region in the one or more regions and the second main terminal one is not coupled to the one or more regions (Hutson fig. 4 electrode 26 coupled to N+ region 18 and electrode 32 is not coupled to one of the N+ regions). Regarding claim 12, the combination of Hutson and Galtie teaches the apparatus according to claim 11, wherein the main terminal two is coupled to at least yet another region in the one or more regions (Fig. 4 electrode 38 coupled to N+ layer 22), the at least yet another region being positioned in the third silicon layer in the second apparatus portion (Fig. 4 N+ layer is positioned within layer 16 and in the apparatus portion to the right of groove 92). Regarding claim 13, the combination of Hutson and Galtie teaches the apparatus according to claim 8, wherein a depth of the trench is configured to be greater than a thickness of the first silicon layer (Hutson fig. 4 groove 92 extends deeper than layer 14 into layer 12 and so it has a greater thickness than layer 14). Regarding claim 14, the combination of Hutson and Galtie teaches the apparatus according to claim 8, wherein the trench and the isolation region are configured to prevent migration of one or more charge carriers between the first and second apparatus portions (Hutson fig. 4 carrier lifetime degrading material 96 and 98 within grooves 92/94 aid in preventing migration of carrier between apparatus sides). Regarding claim 15, the combination of Hutson and Galtie teaches the apparatus according to claim 11, wherein the first apparatus portion is configured to route current upon a bias of main terminal two being higher than a bias of the first main terminal one (Hutson col. 3 “[t]he device shown in FIG. 1 provides symmetrical electrical switching operation somewhat similar to that of conventional triacs upon the application of suitable bias to the three electrodes” and so the apparatus portion to the left of groove 92 routes current upon a biasing of electrode 38 higher than electrode 30). Regarding claim 16, the combination of Hutson and Galtie teaches the apparatus according to claim 15, wherein the second apparatus portion is configured to route current upon a bias of the second main terminal one being higher than a bias of the main terminal two (Hutson col. 3 “[t]he device shown in FIG. 1 provides symmetrical electrical switching operation somewhat similar to that of conventional triacs upon the application of suitable bias to the three electrodes” and so the apparatus portion to the right of groove 92 routes current upon a biasing of electrode 32 higher than electrode 38). Regarding claim 17, the combination of Hutson and Galtie teaches the apparatus according to claim 1, wherein the apparatus is a semiconductor device (Figs. 1/4 symmetrical semiconductor switch 10 is a semiconductor device). Regarding claim 18, the combination of Hutson and Galtie teaches the apparatus according to claim 17, wherein the semiconductor device is a thyristor (Hutson col. 1 “[a] symmetrical switch for providing bidirectional switching is commonly termed a triac and has heretofore generally comprised five layers of alternating semiconductor types” and examiner notes TRIACs comprise a thyristor). Regarding claim 19, the combination of Hutson and Galtie teaches the apparatus according to claim 18, wherein the semiconductor device is a TRIAC semiconductor device (Hutson col. 1 “[a] symmetrical switch for providing bidirectional switching is commonly termed a triac and has heretofore generally comprised five layers of alternating semiconductor types” and so the combination of Hutson and Galtie teaches a TRIAC semiconductor device). Regarding claim 20, Hutson teaches a semiconductor device, comprising: a first silicon layer (Fig. 4 layer 14), a second silicon layer (Fig. 4 layer 12), and a third silicon layer (Fig. 4 layer 16), the first silicon being coupled to the second silicon layer and the second silicon layer being coupled to the third silicon layer (Fig. 4 layers 12/14/16 all coupled to each other); a trench formed in the first silicon layer and in at least a portion of the second silicon layer (Fig. 4 grooves 92/94 formed in layers 14/16 and extending into layer 12 from both directions); an isolation region formed in at least the second silicon layer (Fig. 4 carrier lifetime degrading material 96/98 in grooves 92/94), wherein the trench and the isolation region are configured to separate the semiconductor device into a first semiconductor device portion and a second semiconductor device portion (Hutson col. 5 “[a] groove is formed in each of the outer layers to electrically separate each of the outer layers into two areas”); a first main terminal one and a first gate terminal coupled to a first portion of the first silicon layer (Fig. 4 electrodes 30 and 24 coupled to a portion of layer 14 to the left of groove 92); a second main terminal one and a second gate terminal coupled to a second portion of the first silicon layer (Fig. 4 electrodes 32 and 26 coupled to a portion of layer 14 to the right of groove 92); a main terminal two coupled to the third silicon layer (Fig. 4 electrode 38 coupled to layer 16); and one or more silicon regions in the first silicon layer and in the third silicon layer (Fig. 4 N+ type layers 16/18 in layer 14 and N+ layer 22 within layer 16); wherein the first semiconductor device portion is configured to route current upon a bias of main terminal two being higher than a bias of the first main terminal one (Hutson col. 3 “[t]he device shown in FIG. 1 provides symmetrical electrical switching operation somewhat similar to that of conventional triacs upon the application of suitable bias to the three electrodes” and so the apparatus portion to the left of groove 92 routes current upon a biasing of electrode 38 higher than electrode 30), and the second semiconductor device portion is configured to route current upon a bias of the second main terminal one being higher than a bias of the main terminal two (Hutson col. 3 “[t]he device shown in FIG. 1 provides symmetrical electrical switching operation somewhat similar to that of conventional triacs upon the application of suitable bias to the three electrodes” and so the apparatus portion to the right of groove 92 routes current upon a biasing of electrode 32 higher than electrode 38). Hutson does not appear to teach wherein the isolation region is configured to extend from the trench to the third silicon layer. Galtie teaches wherein the isolation region is configured to extend from the trench to the third silicon layer (Fig. 2 p-type isolating wall 13 extends from a top surface down to a bottom surface). Being in analogous arts, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Hutson with the teachings of Galtie because as both Hutson and Galtie teach suitable and compatible methods for forming an isolating structure in a TRIAC device, it would have been obvious to combine Hutson’s trench filled with a carrier lifetime degrading material that extends partially through the center of the device with Galtie’s p-type isolating wall that extends fully through the center of the device to achieve the predictable result of forming a p-type isolating structure that extends fully through the device in combination with a trench filled with a carrier lifetime degrading material that extends partially through the center of the device. Regarding claim 21, Hutson teaches a method, comprising: providing a first silicon layer (Fig. 4 layer 14), a second silicon layer (Fig. 4 layer 12), and a third silicon layer (Fig. 4 layer 16); coupling the first silicon to the second silicon layer and coupling the second silicon layer to the third silicon layer (Fig. 4 layers 12/14/16 all coupled to each other); forming a trench in the first silicon layer and at least a portion of the second silicon layer (Fig. 4 grooves 92/94 formed in layers 14/16 and extending into layer 12 from both directions); forming an isolation region in at least the second silicon layer (Fig. 4 carrier lifetime degrading material 96/98 in grooves 92/94); coupling a first main terminal one and a first gate terminal to a first portion of the first silicon layer (Fig. 4 electrodes 30 and 24 coupled to a portion of layer 14 to the left of groove 92), coupling a second main terminal one and a second gate terminal to a second portion of the first silicon layer (Fig. 4 electrodes 32 and 26 coupled to a portion of layer 14 to the right of groove 92), and coupling a main terminal two to the third silicon layer (Fig. 4 electrode 38 coupled to layer 16); and forming one or more regions in the first and second portions of the first silicon layer and the third silicon layer (Fig. 4 N+ type layers 16/18 in layer 14 and N+ layer 22 within layer 16). Hutson does not appear to teach wherein the isolation region is configured to extend from the trench to the third silicon layer. Galtie teaches wherein the isolation region is configured to extend from the trench to the third silicon layer (Fig. 2 p-type isolating wall 13 extends from a top surface down to a bottom surface). Being in analogous arts, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Hutson with the teachings of Galtie because as both Hutson and Galtie teach suitable and compatible methods for forming an isolating structure in a TRIAC device, it would have been obvious to combine Hutson’s trench filled with a carrier lifetime degrading material that extends partially through the center of the device with Galtie’s p-type isolating wall that extends fully through the center of the device to achieve the predictable result of forming a p-type isolating structure that extends fully through the device in combination with a trench filled with a carrier lifetime degrading material that extends partially through the center of the device. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to COLE LEON LINDSEY whose telephone number is (571)272-4028. The examiner can normally be reached Monday - Friday, 8:00 a.m. - 5:00 p.m.. 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. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christine Kim can be reached at (571)272-8458. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /COLE LEON LINDSEY/Examiner, Art Unit 2812 /CHRISTINE S. KIM/Supervisory Patent Examiner, Art Unit 2812
Read full office action

Prosecution Timeline

Dec 01, 2023
Application Filed
Jan 30, 2026
Non-Final Rejection — §103, §112 (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
89%
Grant Probability
99%
With Interview (+12.8%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 116 resolved cases by this examiner. Grant probability derived from career allow rate.

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