US 11791432

I'll search for this specific patent number across USPTO sources and litigation dockets.

US 11,791,432 B2 — Summary

Caveat up front: Google Patents/Justia are reliable secondary renderings, but the authoritative full text supplied to me does not include the patent's verbatim Abstract or a clean, numbered Claims section. Where I flag uncertainty below, it reflects an actual gap in what I retrieved rather than a guess.

Bibliographic data (high confidence)

Ownership note: Google Patents lists a 2024-10-23 reassignment to IP Litfin US 2024 LLC captioned "PATENT SECURITY AGREEMENT," with W&WSENS DEVICES, INC. as assignor. That is a security interest, not necessarily a transfer of title; the "current assignee" field still shows W&WSens Devices Inc. I have not verified the recorded instrument.

Abstract

I could not retrieve a verbatim abstract for this specific grant. Family-member abstracts (e.g., US 2017/0194522 A1) read: "Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described… Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s…" Treat that as family-level paraphrase only, not the '432 abstract.

Technical gist

The patent family claims photodetectors (PDs, APDs, SPADs) in which deliberately formed "holes" — voids, dielectric-filled, or differently-indexed volumes — are etched into or grown within the semiconductor (single-crystal Si, Ge, or GeSi-on-Si, often on SOI) to scatter/trap incident light and thereby raise absorption and external quantum efficiency (EQE), while keeping the absorbing "I" region thin enough for GHz-class bandwidth and for monolithic integration with CMOS/BiCMOS on the same chip. The specification defines "hole" broadly as a deliberately formed volume differing from surrounding material in electrical and/or optical properties — solid, dielectric, gas, or vacuum — and explicitly distinguishes holes from isolation trenches. Applications emphasized: data-center/fiber-optic receivers at 850/1300/1550 nm and LiDAR/3D imaging at NIR wavelengths.

Independent claims — plain language

Based on the granted-patent claim listing (Justia), US 11,791,432 has two independent claims (1 and 6):

Claim 1 — pixel array with one hole per pixel.
An integrated single-chip structure with:

• multiple photodetector pixels in a matrix, each having an I-region of semiconductor and only one hole extending into the I-region from a surface, where the hole is (a) inset at least 200 nm from the pixel's surrounding outline and (b) no larger than 1,000 nm across that surface;
• a first doped region of one polarity and a second doped region of the opposite polarity, with the I-region being undoped/less doped and sandwiched between them and electronically interacting with them;
• each pixel responding to light "free of interaction with fixed charge material" (i.e., no fixed-charge film such as the negative-charge layers used in some image sensors) impinging on the pixel, including on the hole, to produce an electrical signal; and
• electrical conduits (wiring) coupled to the pixels to receive those signals;
• with the functional requirement that the hole increases the pixels' effective quantum efficiency (EQE) relative to an identical structure without the hole.

Plain-language effect: a CMOS-image-sensor-style matrix in which a single, small, centered micro-hole per pixel does the light-trapping — and the fixed-charge-material limitation is stated as a negative limitation.

Claim 6 — pixel matrix with isolation trenches plus one hole per pixel.
An integrated structure of pixels in a matrix comprising:

• an I-region of low-doped/undoped semiconductor, plus first and second oppositely doped regions with the I-region between them and interacting electrically;
• isolation trenches extending at least partially into the semiconductor to define the pixels in the matrix;
• each pixel containing a single hole extending in from a surface, the hole having a closed contour on that surface, inset at least 200 nm from the surrounding outline, and no more than 1,000 nm across; and
• electrical conduits to receive the pixels' signals.

Plain-language effect: the same single-micro-hole-per-pixel idea, but the pixel boundaries are set by isolation trenches — which matters because the E.D. Tex. claim-construction dispute over sibling patents is precisely whether a "hole" reads on an isolation trench (see below).

Dependent claims: 2–5 depend from claim 1 (sidewall conformal doping; inverted-pyramid hole; holes of differing sizes across pixels; irregular hole shape). 7–11 depend from claim 6 (trenches extend only partway; a doped region overlying the hole; inverted-pyramid hole; one conduit common to all pixels; trenches/hole filled with solid dielectric).

Discrepancy to flag: the pre-issue publication of this application (US 2021/0242354 A1) had a different claim 1 — an "integrated, single-chip structure" with a photosensitive portion on one side of a substrate and an active CMOS/BiCMOS circuit on the opposite side, with the hole extending deeper than a crystal-plane inverted pyramid. Related claim-style passages (substrate/CMOS two-sided structure; "triplet" avalanche structures; interdigitated-electrode structures) appear in the full text supplied to me. If you need the exact granted claim set and Abstract, pull the USPTO PatentCenter/Patent Public Search document for 17/182,954 rather than relying on the Google Patents rendering.

Litigation / PTAB / CAFC status (as of April 2026)

• District court: W&Wsens Devices Inc. v. Samsung Electronics Co., Ltd., et al., No. 2:24-cv-00854-JRG (E.D. Tex., Marshall, Judge Rodney Gilstrap). Asserted patents in the operative infringement contentions are U.S. 9,525,084; 10,446,700; 10,468,543; 11,621,360; and 12,087,871 (with 12,243,948 also named in the amended complaint). I found no evidence that 11,791,432 itself is asserted in that case. Trial is calendared for August 3, 2026.
• PTAB: Samsung filed IPR2025-00993, -00994, -00995 ('543) and -00996 ('700). Institution was discretionarily denied under §314(a) (duplication with the imminent district court trial; settled expectations; petitioner's 2020 awareness). Petitions for Director Review were denied (Jan. 12, 2026; refunds approved March 2026). None of these involves the '432 patent on the record I retrieved.
• CAFC 2026: No Federal Circuit docket or opinion referencing 11,791,432 was found. I cannot rule out a recently filed notice of appeal that is not yet indexed, but I have no authoritative basis to assert one exists.
• Claim-construction relevance: in the E.D. Tex. case the central dispute is construction of "hole" (W&Wsens: "an absence of material"/"physical void"; Samsung: plain meaning, e.g., not an isolation trench). Because granted claims 1 and 6 of the '432 patent respectively exclude and expressly include isolation trenches, that construction dispute bears directly on this patent's scope.

Explicit uncertainties

1. Exact verbatim abstract for the '432 grant — not retrieved.
2. Exact issued claim set/count for the '432 grant — the Justia listing shows independent claims 1 and 6 and dependents through 11, but the full text I was given contains additional claim-style passages that may reflect the published application rather than the grant.
3. Whether 11,791,432 is or was asserted in any proceeding — no supporting results found; absence of evidence, not proof of absence.
4. Effect of the 2024-10-23 IP Litfin US 2024 LLC security agreement on current title — unverified beyond the Google Patents entry.

I'll search for litigation involving US patent 11791432.

Initial results don't show litigation. Let me search more targeted sources.

Found a key case. Let me verify whether US 11791432 specifically is asserted.

Summary of Findings — US Patent No. 11,791,432

Important upfront conclusion: I found no litigation that specifically identifies US Patent No. 11,791,432 ("Microstructure enhanced absorption photosensitive devices") as an asserted patent. I want to be explicit about that limitation rather than imply otherwise.

Patent identity (confirmed)

Litigation directly naming US 11,791,432

None found. Searching litigation databases and docket sources for the specific number "11791432" returned only patent-database citations (the patent being cited as prior art/reference in other patents), not any complaint, IPR, or court case in which the '432 patent is a patent-in-suit.

Closely related litigation by the same patent owner (for context — NOT confirmed to include the '432 patent)

The '432 patent shares a specification and priority chain with a family of W&Wsens patents that are in active litigation:

W&Wsens Devices Inc. v. Samsung Electronics Co., Ltd. et al

• Plaintiff: W&Wsens Devices Inc.
• Defendants: [Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), Ltd.; Samsung Electronics America, Inc.; (originally also Samsung Semiconductor, Inc. and Samsung Austin Semiconductor LLC)
• Jurisdiction: U.S. District Court, Eastern District of Texas, Marshall Division
• Case No.: 2:24-cv-00854-JRG (Judge Rodney Gilstrap)
• Filing date: October 21, 2024
• Asserted patents (as reflected in the claim-construction record): U.S. Patent Nos. 9,525,084 ('084); 10,446,700 ('700); 10,468,543 ('543); 11,121,271 ('871); 11,621,360 ('360); 11,830,954 ('948). The '432 patent does not appear among these.
• Accused products: Samsung ISOCELL CMOS image sensors (dual-pixel/PDAF, Tetracell/Nonacell) and ISOCELL Vizion time-of-flight sensors (33D, 63D, 931), plus Galaxy end products.
• Status/outcome to date: Claim construction issued (the court construed "hole" as "a void whose primary purpose is to increase the absorption of light entering the void by the light absorbing material abutting the void"). Claims on the '084 patent were dismissed with prejudice as to Samsung's currently existing products (per joint order dated October 7, 2025); the action was dismissed without prejudice as to Samsung Semiconductor and Samsung Austin Semiconductor. The case continued against the remaining Samsung defendants; venue-transfer motion litigation and invalidity-contentions amendment litigation were also docketed.

Related PTAB proceedings (Samsung as petitioner):

• IPR2025-00994, IPR2025-00995, IPR2025-00996 (filed ~May 20, 2025). IPR2025-00995 was terminated October 17, 2025 by discretionary denial of institution (Board denied, and Director Review was subsequently denied 2026-01-12; refund approved 2026-03-09). IPR2025-00996 concerns the '700 patent. These address other family members, not the '432 patent.

Caveats

1. I could not access Docket Navigator or the Unified Patents litigation caselist directly in this session; my findings rely on court filings, Justia/CourtListener, Docket Alarm, Stanford NPE database, and PTAB records surfaced via search.
2. It is possible the '432 patent was added to the Samsung case (or another case) in a later-amended complaint or infringement contention that I did not surface. The '432 patent did not appear in the claim-construction order or the asserted-patent lists I reviewed.
3. I did not find any CAFC appeal or PACER docket expressly listing the '432 patent.

Bottom line: As of the sources reviewed, no litigation specifically asserting US Patent No. 11,791,432 is known. The most relevant active dispute is the related W&Wsens v. Samsung case (E.D. Tex., 2:24-cv-00854-JRG), which asserts sibling patents from the same family but not, on the record I reviewed, the '432 patent. If you need a definitive negative, I'd recommend a direct Docket Navigator or Lex Machina query on the patent number, which I cannot run from here.

Proceedings overview

Zero. As of the USPTO Open Data Portal ingest (the canonical list supplied in this analysis), there are no AIA trial proceedings — no IPR, no PGR, and no CBM — on file against US 11,791,432; the tally is 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials, which means the bottom-line defensive posture is "the patent is entirely untested at the PTAB" — neither hardened by a win nor narrowed by a loss, and with no § 315(e) estoppel running against anyone on this patent.

I re-ran targeted searches for the patent number in a PTAB context and found only patent-database citations of US 11,791,432 as prior art in other patents (e.g., Google Patents listings for US20140246707, US10163948B2), not any petition, institution decision, FWD, or appeal naming it. I could not surface a single AIA trial document bearing this patent number. Per the operating rule for this task ("the default should be 'no PTAB activity on file'"), that is the finding.

No proceedings to enumerate

Because the structured list is empty, there are no per-proceeding entries to write. I will not manufacture proceeding numbers, panels, or claim dispositions. For completeness, the framework fields (type / filed / status / panel / grounds / institution / FWD / settlement / appeal / defensive value) are N/A across the board.

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Context (NOT proceedings on US 11,791,432 — do not cite these as such)

The '432 patent sits in the same W&Wsens specification family that is under attack, and a defendant will inevitably confuse the two. To be explicit: none of the proceedings below names US 11,791,432 as the challenged patent. All of them are Samsung petitions against sibling patents with the same 2013-05-22 priority lineage and overlapping disclosure.

⚠️ Flagged inconsistency with the previously generated Litigation summary. That summary states IPR2025-00995 was terminated 2025-10-17 by discretionary denial with Director Review denied 2026-01-12, and that IPR2025-00996 concerns the '700 patent. The docket evidence I surfaced shows the reverse pairing in part: the 2025-10-17 termination appears on the IPR2025-00996 docket, while IPR2025-00995 (which the petition caption identifies as the '543 patent) shows a denial-of-institution followed by a still-pending Director Review Request as of 2025-11-25. Treat the -00995/-00996 dates in the earlier section as unreliable; the safe statement is that Samsung's family-wide petitions in 2025 were met with discretionary denials and at least one Director Review request, and none of them touched the '432.

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Strategic summary

Claim status on the '432 patent: everything is UNTESTED. There is no FWD, no certificate canceling claims, no adverse judgment, and no reissue or reexamination certificate narrowing the claims. The patent stands as granted on 2023-10-17 with 2034-07-29 adjusted expiration, and every claim — independent and dependent — remains live and unchallenged at the Office. A defendant facing a demand letter on the '432 therefore gets no free invalid-claim defense from any prior PTAB record; conversely, the patent owner gets no "survived IPR" hardening narrative either, because no panel has ever passed on the merits. What the patent owner does get is the benefit of the 2025-2026 institutional climate, which is a real and quantifiable advantage (see below).

Estoppel landscape: essentially clean, which cuts both ways. § 315(e)(2) estoppel attaches only to a petitioner that obtained an FWD on that patent's claims. Because Samsung's IPRs are directed to the '360, '543, '700 and '084 patents — different patents with different claims — no estoppel reaches the '432 patent. That means a defendant who was not previously barred may still raise on the '432 any § 102/§ 103 ground it can support, including art that might have been "reasonably could have raised" in a sibling IPR. The counterweight is timing: PGR is foreclosed (the 9-month post-grant window from 2023-10-17 closed on 2024-07-17 at the latest), so IPR is the only AIA vehicle, and IPR is limited to patents and printed publications under §§ 102/103 — no § 101 or § 112 challenges, and no system-art/public-use grounds. Separately, run a § 315(b) clock check immediately: any defendant served with a complaint alleging infringement of the '432 more than one year before today (2026-09-29) is time-barred from filing an IPR on this patent, full stop. That is the single most important date to verify.

Pattern signals. The petitioner is the same actor across the whole family — Samsung entities (Samsung Electronics Co., Ltd.; Samsung Electronics America, Inc.; Samsung Semiconductor, Inc.; Samsung Austin Semiconductor LLC) — and it filed a wave of companion petitions (IPR2025-00993 through -00997) rather than a single serial attack. That is one petitioner, not a defensive aggregator; Unified Patents does not appear anywhere in this chain. The patent owner (W&Wsens) has litigated PTAB outcomes aggressively on the sibling patents, both by arguing discretionary denial and by opposing Director Review, and it has had substantial success doing so under the current regime. The striking signal for the '432 is selective assertion: W&Wsens chose the '871, '360, '543, '700 and '948 patents for the E.D. Tex. case and did not add the '432 to the claim-construction record or the asserted-patent list. The absence of both assertion and PTAB activity suggests the '432 is being held in reserve — and that whatever its commercial value, it has not yet drawn fire in either forum.

Institutional climate (2025-2026), applied to the '432. Under the changes described in the USPTO's Interim Processes for PTAB Workload Management — discretionary-denial briefing before the merits, Director (now Deputy Director) control of institution for petitions filed after 2025-10-20, and the "settled expectations" line of denials — a hypothetical IPR on the '432 would face headwinds that did not exist when Samsung filed. The '432 is a young patent (granted 2023-10-17), which cuts against settled-expectations denial, but it is asserted-adjacent to a co-pending district court action and shares a specification with patents already before Judge Gilstrap, which invites § 325(d) and Fintiv-type arguments. Realistically, a new petitioner would need a Sotera-type stipulation and a strong merits showing to get traction.

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Recommended next steps

1. If you are a defendant and want PTAB relief on the '432: file early and confirm the § 315(b) clock. There is no PTAB record to lean on. Because no IPR exists, the entire merits case — institution through FWD — has to be built from scratch, and under the current regime the petition will be screened for discretionary denial before the merits are reached. Check the exact date you were served with any complaint alleging the '432; if it is on or before 2025-09-29, you are outside the one-year window and IPR is unavailable.
2. Do not cite the sibling IPRs as invalidating the '432. There is no FWD, no cancellation certificate, and no adverse judgment tied to this patent. Any argument of the form "claims 1-5 have been canceled" is factually wrong here — the claims are all live. The only public Office records to cite for this patent are the file history at USPTO Patent Center (application 17/182,954) and the patent text at Google Patents.
3. If you are the patent owner or a licensee: there is a working narrative — "no one has ever successfully challenged the '432" — but it is an absence of challenge, not a rejection of one. Expect a defendant to argue the reason is that the patent has not been asserted, not that it is unimpeachable. Consider whether the '432 should be added to the E.D. Tex. case now (which would start a § 315(b) clock for the remaining Samsung defendants) or kept in reserve.
4. Watch the 2026 Director Review outcomes on the sibling IPRs as a proxy. If institution denials in IPR2025-00993/94/95 hold up (or if Director Review reverses them), that is your best predictor of how a future '432 petition would fare. The PTAB's public docket is at PTAB E2E; family proceedings are visible on Docket Alarm and the ex parte PTAB pages linked above.
5. Do not overlook non-AIA routes. Because the AIA trial list is empty, ex parte reexamination (§ 302, any time, any person, no § 315(b) bar, but limited to patents/printed publications) and § 282 invalidity in the district court remain open. Neither carries the estoppel exposure of an IPR.
6. Re-verify before relying on this. My finding is based on the ODP structured list (zero) plus web corroboration. The ODP ingest lags recently filed papers. Before filing or answering a demand letter, run a direct PTAB E2E / Docket Navigator / Lex Machina query on "11,791,432" — I could not run those tools directly in this session, and a newly filed, not-yet-indexed petition is the one scenario that would change this answer.

I'll research the assignment record for US 11,791,432 using the available sources.

Let me look for more specific assignment records and the entities involved.

I was unable to retrieve reel/frame numbers or correspondent-of-record names from the sources accessible in this session before hitting the tool-call limit. I will present only what is verifiable from the authoritative patent text (Google Patents legal-events block) and the prior-section findings, and I will flag the gaps explicitly rather than invent reel/frame or attorney data.

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Inventors

Pattern notes:

• No "inventor-departure" signal is present in the way the task describes — the two inventors are the principals of the assignee company, so there is no post-filing exodus preceding a fire-sale. The two names ("Shih‑Yuan Wang" / "Shih‑Ping Wang") recur across the entire W&Wsens family, i.e., the same two individuals are the inventors on essentially the whole portfolio.
• Caveat: I could not independently confirm either inventor's then-current employer beyond the W&Wsens link. Shih-Yuan Wang's historical HP Labs affiliation is documented but is prior history, not confirmed employment as of 2021.

Original assignee

W&Wsens Devices, Inc. — the entity named as applicant at filing (application filed by W&Wsens Devices Inc, 2021‑02‑23) and as assignee/owner on the issued patent (granted 2023‑10‑17).

• Primary line of business: Development of microstructure‑enhanced photodetectors (Si/Ge/GeSi PIN, MSM, APD/SPAD) monolithically integrated with CMOS/BiCMOS ASICs, targeting datacenter optical interconnect, telecom, LiDAR and 3D imaging. The company produced a technical presentation titled "Thin Silicon Photosensors for The Next Generation" (Exhibit 2005 in IPR2025‑00995).
• Did they ship a product embodying the claims? No evidence of a commercial product found. Every surfaced artifact shows development and patent prosecution, followed by litigation — not product sales. This is the classic declared-intent-but-uncommercialized profile.
• Current status: Operating as a patent-holding and asserting entity. It is the plaintiff/patent owner in W&Wsens Devices, Inc. v. Samsung Electronics Co., Ltd. et al., No. 2:24‑cv‑00854‑JRG (E.D. Tex.), and the patent owner in Samsung's IPRs (e.g., IPR2025‑00995 over the '543 patent). No bankruptcy, dissolution, or acquisition found.

Contradiction check vs. prior section: None. The prior section lists the current assignee as "W&Wsens Devices Inc" and a security interest from "IP Litfin US 2024 LLC." The legal-events block in the full text is consistent with that: W&Wsens remains the owner; the IP Litfin record is a security interest, not an ownership conveyance. (See caveat below on the legal effect.)

Assignment timeline

The full patent text (authoritative) shows exactly two post‑filing legal events on Google Patents, both of the "Assigned to…" type — one true assignment and one security interest:

• executed date not stated / recorded 2023‑05‑30 — Reel NNNNNN/NNNN (not retrieved)

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Wang, Shih-Ping; Wang, Shih-Yuan (the named inventors)
  • Assignee: W&WSENS DEVICES, INC.
  • Correspondent: not retrieved — record not accessible in this session.
  • Context: Formalization of inventorship → company ownership. Note the timing anomaly: the application was filed 2021‑02‑23 with W&Wsens as applicant, yet the inventor→company assignment is dated/recorded ~27 months later (2023‑05‑30), shortly before grant (2023‑10‑17). This reads like a nunc pro tunc / confirmatory assignment executed to perfect an unbroken chain of title — a step typically taken in preparation for assertion.

• executed date not stated / recorded 2024‑10‑23 — Reel NNNNNN/NNNN (not retrieved)

  • Conveyance: Patent Security Agreement (security interest / collateral lien — not a transfer of title)
  • Assignor: W&WSENS DEVICES, INC.
  • Assignee: IP LITFIN US 2024 LLC (security-interest holder)
  • Correspondent: not retrieved — record not accessible in this session.
  • Context: Securitization / litigation-finance collateral. Recorded two days after W&Wsens filed suit against Samsung (complaint filed 2024‑10‑21). The timing is consistent with an assignment of patent collateral to a litigation-funding vehicle, not a sale.

Data-limitation statement (important): I could not retrieve the USPTO Assignment Center reel/frame numbers, execution dates, or correspondent-of-record for either entry. I searched but did not surface them. Per the operating rules, I am not fabricating reel/frame or attorney names. The two entries above are taken from the Google Patents "Assigned to…" legal-events text embedded in the authoritative full text. A direct Assignment Center query on patent number 11791432 or application 17/182,954 is required to confirm reel/frame, execution date, and correspondent. Verified search entry point: https://assignmentcenter.uspto.gov/ (search by patent number 11,791,432).

Timeline diagram

timeline
    title Ownership of US 11791432
    2021 : Application filed by W&Wsens Devices Inc
    2023 : Inventors assign rights to W&Wsens Devices Inc
         : Patent granted
    2024 : Patent security agreement to IP Litfin US 2024 LLC
         : W&Wsens sues Samsung on sibling patents

NPE / troll-pattern signals

Verdict

NPE — moderate confidence.

The ownership chain is short and clean (inventors → W&Wsens Devices, Inc. per the 2023‑05‑30 assignment, then a 2024‑10‑23 Patent Security Agreement to IP Litfin US 2024 LLC), so there is no shell-transfer or known-asserter signal. The decisive evidence is circumstantial but concrete: (a) the owner W&Wsens ships no product embodying the claims and instead asserts the portfolio (plaintiff in W&Wsens v. Samsung, E.D. Tex. 2:24‑cv‑00854‑JRG; patent owner in Samsung IPR2025‑00994/‑00995/‑00996), and (b) the litigation-finance-style security agreement executed to IP Litfin US 2024 LLC two days after the complaint was filed signals a funded, assertion-driven monetization model. That is one strong signal (non-practicing owner actively asserting) plus one supporting signal (finance collateral), which lands at moderate rather than high confidence.

Do not treat "moderate" as a default NPE flag on this patent specifically: the prior section established that the '432 patent is not among the W&Wsens patents asserted against Samsung (the asserted set is the '084, '700, '543, '871, '360 and '948 patents). The NPE characterization applies to the owner, not to a proven assertion of this patent.

Verification & gaps (please close before relying on this):

1. Query Assignment Center for patent 11,791,432 / app 17/182,954 to capture reel/frame, execution dates, and correspondent of record for both entries — https://assignmentcenter.uspto.gov/
2. Identify IP Litfin US 2024 LLC's registered-agent address and principals (Delaware/Texas entity search) to determine whether it is a litigation funder or related party.
3. Cross-check the asserted-patent list in the Samsung case's operative contentions for any later addition of the '432 patent.

I'll research the prior-art citations for US 11,791,432. Let me start with targeted searches.

Let me dig deeper into the specific "References Cited" list on the patent.

Search Method and Its Limits (read this first)

I ran targeted searches against USPTO/Google Patents/Justia records for the exact number 11,791,432. Two constraints shaped the result, and I want to state them plainly rather than paper over them:

1. I hit the session's search-step ceiling before I could retrieve the complete front-page "References Cited" block (the full U.S. patent-document list, the foreign patent documents, and the non-patent literature). What I obtained is a partial list from the Justia "Referenced Cited" table, truncated at U.S. Pub. No. 2020/0127154. I did not obtain the foreign-document or NPL sections at all.
2. A citation is not an anticipation holding. The references printed on a patent's face are examiner/applicant citations; the claims issued over them. My §102 analysis below is my own, conducted on the claim language I could retrieve, and is flagged as such.

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A. Verified Patent Identity

This matches the litigation-summary section already generated — no contradiction found between that section and the bibliographic record I retrieved.

Family members that must NOT be treated as prior art (they appear in the same priority chain and on the face of the '432): US 9,530,905; US 9,525,084; US 10,446,700; US 10,700,225; US 10,468,543; US 11,121,271; US 11,309,444; US 11,621,360; US 11,830,954; US 12,087,871; US 16/042,535; US 16/296,985; US 16/528,958; WO2019/089437; WO2022/061016. Any of these that appear in a citation list are self/family citations, not §102 art.

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B. The Critical Date — This Drives Almost Everything

The '432 claims priority to 22 May 2013. Under AIA 35 U.S.C. § 102, a reference only qualifies as prior art if it was:

• §102(a)(1): publicly available (published/patented/on sale) before 22 May 2013; or
• §102(a)(2): the subject of a U.S. patent/application effectively filed before 22 May 2013.

Consequence: the overwhelming majority of the references on this patent's face bear 2015–2020 publication dates. Those are not §102 prior art against the '432 claims, full stop — they were cited as background/related art (largely CMOS image-sensor art illustrating the field, and forward/family citations). This is the single most important analytical point about the citation list.

A second caveat: if an examiner ever contended that particular claims are not entitled to the 2013 priority date (new matter added in a later CIP/later-filed continuation), the later-dated references could be resurrected as §102(a)(1)/(a)(2) art. That is a claim-by-claim priority analysis I cannot complete without the full prosecution history of 17/182,954, which I did not retrieve.

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C. Retrieved Cited U.S. Patent Documents — Citation, Date, and §102 Assessment

Status key:

• NOT ART = post-dates the 22 May 2013 critical date → cannot be §102(a)(1) art; not effectively filed before 2013-05-22 → not §102(a)(2) art.
• QUALIFIES AS ART = pre-22 May 2013 publication → eligible under §102(a)(1)/pre-AIA §102(b).
• Description confidence is noted; I am flagging where I could not independently verify a title rather than inventing one.

Pre-2013 references (only these are §102-eligible)

Post-2013 references (NOT §102 prior art against the '432 claims as written)

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D. What I Could Not Retrieve (explicit gaps)

• The remaining U.S. patent documents after US 2020/0127154.
• The entire "Foreign Patent Documents" section (Google Patents shows the '432 carries foreign-document citations; I did not capture them).
• The entire "Other References" / NPL section (non-patent literature is often where the genuinely anticipatory art lives for this family — e.g., Ge-on-Si SACM APD papers such as the Zaoui et al. OFC/NFOEC 2009 reference the specification itself discusses).
• The "Cited By" (forward citation) list — not prior art, but useful for family/library context.
• The full granted claim set of the '432. The claim text I analyzed (claims 1–22) comes from the pre-grant publication US 2021/0242354 A1 as surfaced by Justia; granted claim numbering/scope may differ, so map my §102 notes to claim language, not claim numbers, until verified against the granted claims.

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E. Bottom Line

1. US 11,791,432 was located and identity confirmed — application 17/182,954, granted 2023-10-17, W&Wsens Devices, Inc. I returned only that number; no similar-number results.

2. Most relevant prior art by critical-date: only the pre-22-May-2013 references can be §102 art at all. Within that set, the only thematically relevant citations are the light-trapping/textured-absorber references — US 2012/0012741 A1 (Vasylyev) and US 2012/0153127 A1 (Hirigoyen et al.) — plus the older sensor/Dabrowski references (US 5,757,057; US 2002/0158252 A1 (Zhang); US 2005/0145779 A1 (Mochizuki); US 2009/0039397 A1 (Chao); US 2010/0117178 A1 (Kim); US 2010/0320444 A1 (Dutta); US 2011/0133060 A1 (Yu); US 2011/0156195 A1 (Tivarus); US 2011/0309331 A1 (Yu); US 2011/0315988 A1 (Yu); US 2012/0153416 A1 (Tanaka)).

3. No §102 anticipation is made out by any reference I examined. Claim 1's combination — an essentially single-crystal I-region with a deliberately formed hole extending deeper than a crystal-plane-defined inverted pyramid, plus an active CMOS/BiCMOS circuit on the opposite side of the substrate — is not disclosed by the pre-2013 image-sensor or light-trapping references, which lack the substrate-through, back-side-circuit monolithic architecture and the crystal-plane-exceeding hole geometry. The post-2013 references (US 2013/0321685 onward, including all the Samsung-era image-sensor art and US 11,309,444) fail at the §102 threshold before reaching the disclosure comparison.

4. Do not treat the face-of-patent citations as an invalidity map. For a true invalidity/anticipation study of the '432, the productive sources are (a) the U.S. and foreign citations I could not retrieve, (b) the NPL section, and (c) the prosecution histories of the parent applications and the IPR petitions Samsung filed against sibling family members (IPR2025-00994/00995/00996, noted in the prior section), which will contain the art Samsung believes is closest — though note those petitions target siblings, not the '432.

Confidence statement: I am highly confident in the patent's identity, the priority date, and the date-based §102 conclusions. I have low confidence in the descriptive characterizations of individual references (most are flagged "not verified"), and I could not complete the citation list. I would not rely on this as a final invalidity opinion without pulling the full front page of the '432 (e.g., the USPTO PatentCenter PDF or Google Patents "Citations" tab) and the granted claim set.

I'll first try to retrieve the actual prior-art references listed on this patent's page, plus the claim text, since the supplied full text was truncated before the claims and did not include the "Prior Art"/"References Cited" section.

I have good context now. Let me try to pull the specific "References Cited" (prior-art) list and the issued claim set, which the truncated text omitted.

Obviousness Analysis — U.S. Patent No. 11,791,432 (35 U.S.C. § 103)

0. Scope, inputs, and an explicit flag about the "Prior Art section"

Flag — contradiction with the task instruction. The task directs me to "use the results from the Prior Art section of this page." The full patent text supplied to me is truncated: it ends mid-sentence in the FIG. 8 discussion of the Detailed Description and therefore contains neither the issued claims nor the Google Patents "References Cited (56)" / "Prior Art" tables. I attempted to retrieve that table directly (searches targeting patents.google.com/patent/US11791432B2, Justia, and FreePatentsOnline) and could not surface the examiner-cited reference list for the '432 patent specifically. What I could retrieve are the family's "Cited By" lists and the other family members' citation tables.

I am therefore grounding this analysis on two substitute sources, and I say so rather than pretend otherwise:

1. References cited on the face of the '432 specification itself (on-record art — these are named in the patent text and are the closest thing to "the Prior Art section of this page" that I could obtain).
2. Well-known contemporaneous art in the field, clearly labelled as such and hedged where my confidence is less than high.

If you have the actual IDS/"References Cited" table, the grounds below should be re-mapped onto it before being relied on. This is a technical/attorney-style analysis, not a validity or freedom-to-operate opinion.

Critical date note. The '432 patent's claims are entitled to the family priority date of 2013-05-22 only to the extent the claims are supported by that disclosure (the application itself was filed 2021-02-23 as a continuation). This matters enormously: references published after 2013-05-22 — e.g., Berenschot et al. (2013), Seyedi et al. (2014), Ren et al. (Feb. 2014) — are not prior art against claims entitled to the 2013 date, even though the specification cites them (they were cited in later-filed family members). I therefore confine the primary grounds to pre-May-2013 art.

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1. The claims to be analyzed

Recovered from the pre-grant publication of this application, US 2021/0242354 A1 (the closest available text to the issued claims; the granted claims may have been amended, which is a further caveat):

Claim 1 (independent). An integrated, single-chip structure comprising:

• a photosensitive portion at one side of a substrate and an active CMOS or BiCMOS electronic circuit at an opposite side of the substrate;
• the photosensitive portion comprising at least one photodetector having a P-doped region, an N-doped region, and an I-region of low-doped or undoped semiconductor material between the N- and P-doped regions, with at least one hole deliberately formed to extend into said photosensitive portion;
• wherein the I-region is essentially single-crystal semiconductor material having inherent crystal planes, and the at least one hole extends into the photosensitive portion to a depth exceeding a depth of an inverted pyramid hole with sides along said crystal planes;
• the active circuit comprising plural active electronic elements;
• connecting electrodes to carry photodetector signals to the active circuit; and output electrodes from the active circuit.

Claims 2–10: vertical arrangement variants (hole through one/toward the other doped region; doped material on hole sidewalls; I-region at closed end; hole through both doped regions; plural holes/plural photodetectors; APD; SPAD).

Claims 11–19: lateral arrangement variants of the same features.

Claim 20 (independent). I-regions of a first semiconductor laterally spaced by deliberately formed first holes; regions of the first semiconductor doped to one polarity; regions of a different second semiconductor forming "triplets" (opposite-polarity region laterally between two same-polarity regions); adjacent first-semiconductor regions spaced by the triplets; illumination concurrently illuminating plural holes contributes to a single electrical signal; and the second-semiconductor regions configured as avalanche structures.

Claims 21–22: first and second interdigitated electrodes; and (claim 22, partially retrieved) vertical spacing of the first-semiconductor doped regions from the second-semiconductor regions.

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2. Level of ordinary skill in the art (POSITA)

A POSITA here would be a device physicist/process engineer with a graduate degree (or equivalent experience) in semiconductor optoelectronics and ≥3–5 years in Si photonics, Ge-on-Si epitaxy, CMOS/BiCMOS integration, and photodetector design. He or she would be familiar by 2013 with: Ge/Si separate-absorption-charge-multiplication (SACM) APDs, interdigitated metal-semiconductor-metal (MSM) detectors, back-side-illuminated (BSI) CMOS image sensors, and the photovoltaic light-trapping literature on nanostructured Si. That breadth is what makes the combinations below legally and technically credible.

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3. Prior art available (pre-May-2013)

3(a) References cited within the '432 specification (on-record; safe to rely on)

3(b) Well-known art (hedged)

• Back-side-illuminated CMOS image sensors (photosensitive array on one face of a thinned substrate, readout CMOS on the opposite face / same die with TSVs) — mature, ubiquitous art by the mid-2000s, e.g. commercially shipped BSI sensors and BSI process patents (the STMicroelectronics/Crolles BSI filings US 2012/0261732 A1 and US 2012/0261783 A1 are representative of the genre, though I retrieved those from a different patent's citation list and cannot confirm they appear on the '432 record).
• Interdigitated MSM photodetectors, including Ge MSM devices, and interdigitated lateral PIN photodiodes — long-established detector topologies.
• Guard-ring / reach-through / triplet doped-region geometries in APDs (N-P-N or P-N-P lateral structures used to control edge breakdown and define the multiplication zone).

I have not verified the examiner's actual citations for '432, so I do not assert that any specific one of the (b) references was before the examiner.

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4. Ground 1 — Claim 1 obvious over Kang 2009 in view of Garnett & Yang 2010, further in view of BSI-CMOS art

Element mapping

Motivation to combine (KSR factors)

1. Express problem recognized in the field and conceded by the specification itself. The patent's own Background states that Si at 850 nm has an absorption coefficient of only ~700 cm⁻¹ and Ge at 1550 nm only ~459 cm⁻¹; obtaining adequate quantum efficiency therefore requires a thick I-region, which "becomes so large that the device's maximum bandwidth … becomes too low." Decoupling absorption from physical thickness is thus the known problem the field was trying to solve — and Garnett & Yang/Lin & Povinelli supply the known solution (micro/nanostructure light-trapping). KSR makes this the paradigm case: a known problem + a known, off-the-shelf solution in the same field.
2. Kang 2009 explicitly provides the "monolithic with Si" motivation, and the specification itself acknowledges Ge/Si SACM APDs (citing Kang 2009 and Zaoui 2009) as the state of the art.
3. Predictable result. Garnett & Yang quantify the enhancement (73×) and Lin & Povinelli explain the design levers (lattice constant, hole diameter). Adopting those levers on Kang's Ge I-layer is a predictable application of a known technique yielding a known benefit (higher QE at the same absorber thickness, or same QE at lower thickness/higher bandwidth).
4. "Obvious to try." The design space (hole diameter ~500–1700 nm, period ~1000–2500 nm, square/hexagonal lattice) is small, finite, and enumerated in the art; the specification itself claims only generic ranges.
5. BSI/opposite-side integration is a mere architectural placement of the readout circuit on the opposite face — a known packaging/optical-fill-factor solution in image sensors — with no unexpected interaction with the hole array.

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5. Ground 2 — Claim 1 obvious over Michel et al. (or a Ge-on-Si PD patent) in view of Lin & Povinelli 2009 / Hu & Chen 2007, and Sato/Berenschot

This is a variant ground that maps the same elements with a different primary reference, and additionally addresses the "depth exceeding an inverted pyramid hole" limitation.

Key insight on the inverted-pyramid limitation. The limitation is defined relative to the self-terminating anisotropic-etch geometry: on (100) Si, KOH stops on the (111) planes to give a 54.7°-sidewall pyramid of fixed depth/diameter ratio (Sato; the specification itself cites Sato and Berenschot and explains the 54.7° result). The claim simply requires holes deeper than that self-limited pyramid — i.e., a non-crystallographic, high-aspect ratio hole such as a dry/RIE/ICP-etched hole. The art supplies:

• the anisotropic-etch teaching that defines the reference depth, and
• ample motivation and capability (dry etching, DRIE, Damascene) to etch deeper, since the whole point of the exercise — as the background concedes — is to lengthen the effective optical path.

The fact that the specification describes using a wet KOH etch after a dry etch to form inverted pyramids confirms that the deep-hole vs. pyramid geometry was a known, deliberate design choice, not an invention. Under KSR this is at most an obvious design choice.

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6. Ground 3 — Claim 20 obvious over Kang 2009 / Zaoui 2009 (SACM Ge/Si APD) in view of the hole-array teachings

Claim 20's distinguishing elements are (i) the "triplet" of a second semiconductor (an opposite-polarity region sandwiched between same-polarity regions) and (ii) using those regions as avalanche structures, plus the hole array.

• Element (i) is the well-known guard-ring / field-control / charge-sheet construction used in SACM APDs to define and confine the multiplication region and prevent edge breakdown — expressly disclosed in Ge/Si SACM APD art (Kang 2009; Zaoui 2009, both cited by the patent).
• Element (ii) is inherent in any APD.
• The hole array comes from Garnett & Yang / Lin & Povinelli.
• The "illumination concurrently illuminating plural holes contributes to a respective single electrical signal" limitation requires only a single detector electrode pair collecting from a hole array — i.e., the ordinary configuration of any arrayed-hole photodiode, and expressly taught by Garnett & Yang (one cell/one contact pair over many nanostructures).

Motivation, and it is strong: the record (as reflected in the family's PTAB petition excerpt the search surfaced) states that with nano/microstructure holes the low-doped region can be thinner by 2–10×, dropping avalanche bias from a conventional −80 to −100 V to about −10 to −45 V, and that this "cannot be achieved with conventional Si and/or GeSi and/or Ge APD." That is precisely the kind of express, articulated motivation that makes the combination of hole-array + APD non-inventive.

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7. Dependent claims 2–19, 21–22

These add only conventional, well-documented variations and are obvious over the same grounds plus ordinary design choices:

• Vertical vs. lateral arrangement (2, 11) — two standard PIN topologies; the specification itself calls them alternatives.
• Hole through one/both doped regions; doped material on hole sidewalls; I-region at the closed end (3–7, 12–15, 17) — direct consequences of where the etch stops, an obvious parameter to optimize for series resistance and field profile.
• Plural holes / plural photodetectors (8, 16) — the pixel/array concept of BSI CMOS image sensors and of Garnett & Yang.
• APD (9, 18) and SPAD (10, 19) — Kang 2009 / Zaoui 2009 for APD; SPADs in Si are old art.
• Interdigitated electrodes (21) — the classic MSM/interdigitated lateral PD topology, explicitly used in the specification's FIG. 1 and known throughout the art.
• Vertical spacing of first- vs. second-semiconductor doped regions (22) — a routing/layout choice.

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8. Secondary considerations / possible rebuttal (with an honest assessment)

A patent owner would likely argue:

1. "Skilled artisans were not motivated to put holes in a photodiode I-region; the nanowire literature is solar-cell art." — Weak. The problem (weak absorption near the band edge) is identical; KSR and In re ICON permit analogous-arts reasoning here, and the specification itself imports the solar-cell references (Garnett, Hu, Lin, Ren) as its own evidentiary support. An applicant who cites the art as his own enabling disclosure can hardly call it non-analogous.
2. "The 'depth exceeding an inverted pyramid' limitation is not taught." — Moderately strong on the bare words, but successfully rebutted by the reasoning in §5 (it is a relative-depth limitation over a self-terminating etch, and deeper etching is the obvious response to the conceded thin-absorber problem).
3. Long-felt need / commercial success — The specification asserts a "long-felt need" for Si/Ge-on-Si at 25 Gb/s monolithically integrated. Under Graham v. John Deere both a long-felt need and unexpected results can rebut obviousness. But a long-felt need cuts against the patent owner where the art already contained the solution: a known solution to a long-felt need is stronger evidence of obviousness (KSR). Also note the related W&Wsens family litigation is at an early stage; there is no adjudicated nexus or commercial-success finding to invoke.

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9. Where the prima facie case is weakest (candid limitations)

• I do not have the examiner's actual cited references for '432, nor the issued claim set; the claim text used is from the pre-grant publication and could differ.
• The "essentially single-crystal … depth exceeding an inverted pyramid" language is the most defensible hook if the owner argues the art discloses only porous/random/amorphous texturing rather than designed, single-crystal, non-self-terminating holes. A strong § 103 case must therefore pair a specific deep-dry-etch/ordered-array reference with the inverted-pyramid reference, not rely on generic "black silicon."
• Claim 20 is the least vulnerable claim: its "triplets" of a second, different semiconductor with concurrent multi-hole single-signal collection is a more specific architecture, and a robust ground there requires a SACM/guard-ring reference that clearly arranges opposite-polarity regions between same-polarity regions in the second material.
• The family is already the subject of Samsung IPRs (IPR2025-00994/995/996) on sibling patents — one was denied institution (IPR2025-00995) — which is a signal both that the art is crowded and that reaching institution-quality § 103 grounds on this family is not trivial.

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10. Bottom line

On the record I can reconstruct, claims 1–19 of US 11,791,432 are prima facie obvious under § 103 over the classic combination of (i) a Ge-on-Si / Si PIN or SACM APD monolithically integrated with Si (Kang 2009; Michel et al.; Zaoui 2009), (ii) an ordered micro/nanostructure hole array for absorption enhancement in Si/Ge (Garnett & Yang 2010; Lin & Povinelli 2009; Hu & Chen 2007), and (iii) a photosensitive-portion-on-one-side / CMOS-on-the-other-side architecture (BSI-CMOS art), with the anisotropic-etch references (Sato; Berenschot) supplying the "inverted pyramid" reference geometry for the depth limitation. Claim 20 is more defensible and would require a more targeted SACM/guard-ring "triplet" reference.

Unresolved and important: the instruction to "use the results from the Prior Art section of this page" could not be fully complied with because that section was absent from the supplied full text and I could not retrieve the '432-specific "References Cited" list. The grounds above use the references cited within the patent and well-known art as substitutes; before this is relied upon, the grounds must be re-mapped onto the actual examiner citations and the actual issued claim language. I have deliberately not fabricated any reference identifier, and where I am less than highly confident (e.g., the specific BSI process patents), I have said so.