US 9130074

Patent Summary: US 9,130,074

Date: April 26, 2026

A concise summary of US Patent 9,130,074 is provided below, including details of ongoing litigation involving the patent.

Title: High-efficiency solar cell structures and methods of manufacture.

Assignee: The current assignee is First Solar, Inc. The original assignee was Tetrasun Inc.

Inventors: Oliver Schultz-Wittmann, Denis DeCeuster.

Filing Date: April 21, 2010.

Issue Date: September 8, 2015.

Abstract: The patent discloses various solar cell compositions that generally include a central substrate, along with one or more conductive layers, antireflection layers, and passivation layers, as well as electrodes. It describes multifunctional layers that combine properties such as passivation, transparency, and sufficient conductivity for vertical carrier flow. The patent also covers manufacturing methods, including single-side Chemical Vapor Deposition (CVD) processes and thermal treatments for layer formation and conversion.

Plain-Language Overview of Independent Claims

This patent contains eight claims, with claim 1 being the sole independent claim.

Claim 1: This claim outlines a method for fabricating a solar cell. The process starts with a silicon wafer and involves depositing or growing electrically passivating interface layers on both its front and back surfaces. Following this, electrically passivating and conductive film layers are deposited over these interface layers. A crucial step is a thermal treatment at a temperature of at least 500°C. The claim specifies that this heat treatment is designed to achieve one or more of the following: crystallize an amorphous silicon-containing compound into a polycrystalline film, enhance the optical transmissivity of the film, activate doping atoms within the film, and/or cause dopant atoms to diffuse into the silicon wafer to create a p-n junction or a high-low junction. The final step is adding metal electrodes to the structure.

Litigation Update

As of early 2026, US Patent 9,130,074 is the subject of significant legal action. First Solar, Inc. has initiated an investigation through the U.S. International Trade Commission (ITC) into Tunnel Oxide Passivated Contact (TOPCon) solar products. The investigation targets numerous companies, including major solar manufacturers, for alleged infringement of this patent.

First Solar acquired the patent through its 2013 purchase of TetraSun Inc. The company has filed lawsuits in the United States District Court for the District of Delaware against JinkoSolar and Canadian Solar, among others, for alleged infringement of the '074 patent. In January 2026, the U.S. Patent and Trademark Office (USPTO) denied petitions filed by JinkoSolar, Canadian Solar, and Mundra Solar that sought to invalidate this and a related patent, strengthening First Solar's position in the ongoing litigation. This patent is central to First Solar's efforts to protect its intellectual property related to TOPCon solar cell manufacturing technology.

US Patent 9,130,074 has been involved in several litigation proceedings, primarily initiated by the current assignee, First Solar, Inc., to enforce its intellectual property rights related to Tunnel Oxide Passivated Contact (TOPCon) solar technology.

Known litigation involving US Patent 9,130,074 includes:

• Plaintiff(s): First Solar, Inc.

  • Defendant(s): JinkoSolar and its related entities.
  • Jurisdiction: United States District Court for the District of Delaware.
  • Case Number: Not explicitly provided in the search results, but referenced as pending.
  • Filing Date: February 25, 2025.
  • Outcome/Current Status: Ongoing patent infringement lawsuit. JinkoSolar filed an Inter Partes Review (IPR) against the patent on July 18, 2025, seeking to invalidate claims 1-8, but this IPR petition was subsequently denied by the USPTO Director on January 20, 2026, leaving the patent intact.

• Plaintiff(s): First Solar, Inc.

  • Defendant(s): Canadian Solar Inc. and its affiliates.
  • Jurisdiction: United States District Court for the District of Delaware.
  • Case Number: 1:25-cv-00582.
  • Filing Date: May 9, 2025.
  • Outcome/Current Status: Ongoing patent infringement lawsuit. Canadian Solar (USA) Inc. petitioned for Inter Partes Review (IPR2025-01130) of the '074 patent on August 22, 2025, seeking to invalidate claims 1-8. This IPR petition was subsequently denied by the USPTO Director on January 20, 2026, leaving the patent intact.

• Petitioner(s) for IPR: Mundra Solar

  • Patent challenged: US Patent No. 9,130,074 (along with US Patent No. 9,666,732).
  • Jurisdiction: U.S. Patent Trial and Appeal Board (PTAB).
  • Case Number: Not explicitly provided for Mundra Solar's challenge of '074, but IPR2025-01432 (filed by Canadian Solar) and IPR2025-01130 (filed by Canadian Solar) were mentioned in relation to invalidation efforts.
  • Filing Date: Not explicitly provided for Mundra Solar's IPR petition against '074, but their petitions were among those denied on January 20, 2026.
  • Outcome/Current Status: The U.S. Patent and Trademark Office (USPTO) denied Mundra Solar's petition seeking to invalidate US Patent No. 9,130,074 on January 20, 2026.

Proceedings overview

Two AIA trial proceedings have been filed against US patent 9,130,074, both of which are Inter Partes Reviews (IPRs) and both were denied institution. This gives a defendant a challenging defensive posture through PTAB, as the patent has survived two IPR challenges without any claims being invalidated.

IPR2025-01432 — Canadian Solar (USA) Inc. et al. v. Oliver Schultz-Wittmann et al

• Type: Inter Partes Review
• Filed: 2025-08-22
• Status: Discretionary Denial - The PTAB declined to institute the IPR.
• Judge panel: Not publicly available in the provided information.
• Petition grounds: Not publicly available in the provided information.
• Institution decision: Denied - 2026-01-21. The panel's reasoning for discretionary denial is not detailed in the provided information, but the status indicates it was denied institution.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable.
• Appeal: Not applicable.
• Defensive value: This proceeding indicates that Canadian Solar's challenge to the patent through IPR was unsuccessful, and no claims were invalidated. This makes an IPR-based defense harder for parties facing assertion of this patent on the grounds raised by Canadian Solar.

IPR2025-01130 — JinkoSolar Holding Co., Ltd. et al. v. Oliver Schultz-Wittmann et al

• Type: Inter Partes Review
• Filed: 2025-07-18
• Status: Discretionary Denial - The PTAB declined to institute the IPR.
• Judge panel: Not publicly available in the provided information.
• Petition grounds: Not publicly available in the provided information.
• Institution decision: Denied - 2025-12-23. The panel's reasoning for discretionary denial is not detailed in the provided information, but the status indicates it was denied institution.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable.
• Appeal: Not applicable.
• Defensive value: This proceeding indicates that JinkoSolar's challenge to the patent through IPR was unsuccessful, and no claims were invalidated. This makes an IPR-based defense harder for parties facing assertion of this patent on the grounds raised by JinkoSolar.

Strategic summary

All eight claims of US 9,130,074 remain SUSTAINED and UNTESTED on the merits at the PTAB, as both IPRs filed against the patent were denied institution on discretionary grounds. This means that the PTAB did not reach the merits of the patentability challenges, and thus no claims were invalidated or even substantively reviewed in a trial. The patent owner, First Solar Inc., has successfully defended against these initial challenges at the institution phase.

The estoppel landscape is therefore somewhat unique. While the petitions were denied, the exact nature of the discretionary denial (e.g., related to parallel district court litigation, insufficient grounds, or another factor) would dictate the precise preclusive effect. However, typically, a denial of institution does not result in statutory estoppel under 35 U.S.C. § 315(e)(2) for the petitioner because a trial was not instituted. Therefore, theoretically, the same petitioners (Canadian Solar and JinkoSolar) could potentially raise the same or similar prior-art grounds in other venues, or different petitioners could bring new IPRs. The current assignee, First Solar Inc., has been aggressively pursuing litigation, as evidenced by the ITC investigation and Delaware District Court lawsuits, and their success in fending off these IPRs at the institution stage signals a strong defense of their intellectual property.

Recommended next steps

Given that both IPRs were denied institution, a defendant currently facing assertion of this patent would need to thoroughly analyze the reasons for the discretionary denials in IPR2025-01432 and IPR2025-01130. This information is critical to understand what arguments or procedural hurdles led to the denial, and whether similar PTAB challenges could be structured differently to overcome those issues. As the patent remains strong from a PTAB perspective, exploring non-PTAB defensive strategies, or identifying novel prior art not previously presented, would be crucial.

To obtain the specific reasoning for the discretionary denials, one would need to access the institution decisions for IPR2025-01432 and IPR2025-01130 via the USPTO PTAB E2E system.

Inventors

• Oliver Schultz-Wittmann (Tetrasun Inc.)
• Denis DeCeuster (Tetrasun Inc.)

Original assignee

The original assignee was Tetrasun Inc. Tetrasun Inc. was a solar technology company focused on high-efficiency silicon solar cells. It was acquired by First Solar, Inc. in 2013, and its operations were integrated into First Solar.

Assignment timeline

• 2011-11-15 (executed) / recorded 2011-12-07 — Reel 027582/0268
  • Conveyance: Assignment
  • Assignor: Denis Deceuster
  • Assignee: Tetrasun Inc.
  • Correspondent: Matthew J. Van Eman, The Law Offices of Van Eman & Van Eman LLC, 1310 E. Main St., Ste. 101, Madison, WI, 53703
  • Context: Transfer of inventor's interest to original assignee
• 2011-11-15 (executed) / recorded 2011-12-07 — Reel 027582/0268
  • Conveyance: Assignment
  • Assignor: Oliver Schultz-Wittmann
  • Assignee: Tetrasun Inc.
  • Correspondent: Matthew J. Van Eman, The Law Offices of Van Eman & Van Eman LLC, 1310 E. Main St., Ste. 101, Madison, WI, 53703. This correspondent appears multiple times in this chain.
  • Context: Transfer of inventor's interest to original assignee
• 2013-05-10 (executed) / recorded 2013-06-25 — Reel 030043/0187
  • Conveyance: Assignment
  • Assignor: Tetrasun, Inc.
  • Assignee: First Solar, Inc.
  • Correspondent: Joseph F. Ruocco, 350 W. Washington Street, Suite B, Tempe, AZ, 85281
  • Context: Acquisition of Tetrasun Inc. by First Solar, Inc.
• 2025-02-24 (executed) / recorded 2025-03-05 — Reel 065848/0259
  • Conveyance: Assignment
  • Assignor: TETRASUN, INC.
  • Assignee: FIRST SOLAR, INC.
  • Correspondent: Christopher L. Makay, 350 W. Washington Street, Suite B, Tempe, AZ, 85281
  • Context: Internal corporate reorganization or re-recording of prior acquisition for clarity.
• 2025-09-11 (executed) / recorded 2025-09-15 — Reel 066795/0369
  • Conveyance: Security Agreement
  • Assignor: FIRST SOLAR, INC.
  • Assignee: JPMORGAN CHASE BANK, N.A.
  • Correspondent: Amy L. Van Blaricom, 200 West Street, New York, NY, 10282
  • Context: Patent used as collateral for a loan or financing agreement.

Timeline diagram

timeline
    title Ownership of US 9130074
    2010 : Application filed by Tetrasun Inc
    2011 : Inventors assign to Tetrasun Inc
    2013 : Assigned to First Solar Inc
    2015 : Patent issued
    2025 : Tetrasun re-assigns to First Solar
         : Security agreement to JPMorgan Chase

NPE / troll-pattern signals

1. Shell-entity transfer — not present. All assignees appear to be operating companies.
2. Known asserter in the chain — not present. First Solar, Inc. is a major operating company in the solar industry. JPMorgan Chase Bank, N.A. is a financial institution, holding the patent as collateral.
3. Repeat correspondent across the chain — present. Matthew J. Van Eman of The Law Offices of Van Eman & Van Eman LLC is listed as the correspondent for both inventor assignments to Tetrasun Inc. (Reel 027582/0268). While not directly indicating an NPE, it shows consistent legal representation for the early assignments. Christopher L. Makay (350 W. Washington Street, Suite B, Tempe, AZ, 85281) also appears twice, representing the assignor and assignee in the 2013 and 2025 assignments involving First Solar.
4. Cascading transfers — not present. The transfers are spaced out over several years, reflecting business acquisitions and re-recordings rather than rapid transfers between shell entities.
5. Pre-litigation transfer — unclear. The most recent assignment (excluding the security agreement) involving a change of ownership from Tetrasun to First Solar was in 2013. The patent was subsequently re-assigned from Tetrasun to First Solar in February 2025 (Reel 065848/0259). Given that litigation was initiated in early 2026, this 2025 re-assignment might be considered somewhat close to the litigation, although it's listed as a re-assignment from the previous assignee (Tetrasun) back to the current owner (First Solar), which could be an internal clarification rather than a new transfer for assertion purposes. The security agreement in September 2025 (Reel 066795/0369) is also close to the litigation, but this represents collateral, not a transfer for assertion.
6. Bankruptcy fire-sale — not present. There is no indication of Tetrasun Inc. or First Solar, Inc. undergoing bankruptcy proceedings leading to the sale of this patent.
7. Privateering — not present. First Solar, Inc. is directly asserting the patent.
8. Defensive aggregator (anti-NPE) — not present. The patent is currently assigned to First Solar, Inc., an operating company.

Verdict

Operating-company assertion. First Solar, Inc., a major operating company, acquired the patent as part of its acquisition of Tetrasun Inc. in 2013, and it is currently asserting the patent against competitors in the solar industry. The recent assignments in 2025 (Reel 065848/0259 and Reel 066795/0369) appear to be either internal reorganizations/clarifications or a security agreement, rather than transfers to a shell entity for assertion.

For verification, refer to the USPTO Patent Assignment Search: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US patent 9,130,074, I will examine the patent citations listed within the patent document itself. Since the full text of the patent is provided, I will directly extract this information from the "Prior Art Citations" or "References Cited" section, which is typically found after the detailed description and before the claims.

Based on the provided patent text, I will identify and describe the cited prior art references.

Prior Art Analysis for US Patent 9,130,074

The US Patent 9,130,074, titled "High-efficiency solar cell structures and methods of manufacture," lists several prior art documents. A thorough analysis of these citations is crucial to understand the scope of the invention and potential anticipation under 35 U.S.C. § 102.

The patent itself references previously filed applications which are incorporated by reference:

1. U.S. Provisional Application No. 61/171,194

   • Full Citation: U.S. Provisional Application entitled “High-Efficiency Solar Cell Structures and Methods of Manufacture,” filed 21 Apr. 2009 and assigned application number 61/171,194.
   • Publication/Filing Date: April 21, 2009.
   • Brief Description: This provisional application is the basis for the current patent and is incorporated by reference in its entirety. It generally discloses high-efficiency solar cell structures and methods of their manufacture.
   • Potential Anticipation: As the foundational provisional application, it would directly anticipate all claims of US 9,130,074 if the claimed subject matter is adequately disclosed within it, as the priority date for the '074 patent is April 21, 2009, based on this provisional application.

2. U.S. Provisional Application No. 61/171,187

   • Full Citation: U.S. Provisional Application entitled “Method for Forming Structures in a Solar Cell,” filed 21 Apr. 2009 and assigned application No. 61/171,187.
   • Publication/Filing Date: April 21, 2009.
   • Brief Description: This application details a method for forming conductive contact/heterocontact patterns on a solar cell surface, involving forming a thin conductive layer and then ablating a majority of it with a laser to leave the pattern. It also covers self-aligned metallization and contact formation through passivation/antireflective layers to a semiconductor layer.
   • Potential Anticipation: This reference could potentially anticipate aspects of claims related to the formation of metal electrodes and their interaction with underlying layers, specifically those mentioned in Claim 1 regarding "providing metallization as electrodes."

3. U.S. Provisional Application No. 61/171,491

   • Full Citation: U.S. Provisional Application entitled “Localized Metal Contacts By Localized Laser Assisted Reduction Of Metal-Ions In Functional Films, And Solar Cell Applications Thereof,” filed 22 Apr. 2009 and assigned application number 61/171,491.
   • Publication/Filing Date: April 22, 2009.
   • Brief Description: This application describes a method for forming electrical contacts in a solar cell layer by selectively modifying a material in the layer using laser irradiation. The remaining regions of the layer can function as transparent, conductive, anti-reflective, and/or passivation films.
   • Potential Anticipation: Similar to the previous provisional application, this reference could anticipate aspects of Claim 1 concerning the "providing metallization as electrodes" step, particularly where the metallization process involves localized modification of a functional film using laser technology.

4. International Patent Application No. PCT/US2010/031874

   • Full Citation: Commonly-assigned, co-filed International Patent Application entitled “Method for Forming Structures in a Solar Cell,” filed as and assigned application number PCT/US2010/031874.
   • Publication/Filing Date: April 21, 2010.
   • Brief Description: This international application is related to the U.S. Provisional Application 61/171,187 and describes methods for forming conductive contact patterns, including laser ablation of a thin conductive layer and self-aligned metallization.
   • Potential Anticipation: As a co-filed application based on one of the provisional applications, this PCT application would also potentially anticipate elements of Claim 1 related to metallization if its content aligns with the earlier provisional.

5. International Patent Application No. PCT/US2010/031881

   • Full Citation: Commonly-assigned, co-filed International Patent Application entitled “Localized Metal Contacts By Localized Laser Assisted Conversion Of Functional Films In Solar Cells,” filed as and assigned application No. PCT/US2010/031881.
   • Publication/Filing Date: April 21, 2010.
   • Brief Description: This international application is related to U.S. Provisional Application 61/171,491 and describes methods for forming localized electrical contacts in functional films of solar cells using selective laser irradiation.
   • Potential Anticipation: Similar to the other co-filed PCT application, this would potentially anticipate aspects of Claim 1 related to "providing metallization as electrodes" and the creation of contacts through selective laser processing.

It's important to note that these are all related applications by the same assignee/inventors and are incorporated by reference, meaning their content forms part of the overall disclosure of US 9,130,074 and influences its priority date and claim scope. For a true prior art search beyond the patent family, one would typically consult the "References Cited by Examiner" section of the patent's front page or a patent database that lists all cited prior art, not just those incorporated by reference by the applicant. However, based on the prompt's instructions and the provided text, these are the direct references given within the patent's description. The independent claim (Claim 1) describes a method of fabricating a solar cell, including steps of depositing layers, thermal treatment, and adding metal electrodes. The mentioned provisional and PCT applications, particularly those related to forming structures and localized metal contacts, would directly bear upon the novelty of the metallization step in Claim 1. The thermal treatment step, which includes crystallizing amorphous silicon, increasing optical transmissivity, activating dopants, and diffusing dopants to form junctions, is a core element of Claim 1 and would be anticipated if disclosed in the incorporated applications.

The provided patent text, including its "Prior Art keywords" and "Prior art date," does not contain a list of specific prior art references (e.g., patent numbers, publications) that can be combined to perform a detailed obviousness analysis under 35 U.S.C. § 103 for US Patent 9,130,074. The "Prior art keywords" (silicon, layer, conductive, type, doped) and the "Prior art date" (April 21, 2009) indicate the general technical field and the relevant timeframe for prior art but do not provide specific documents or disclosures.

While the "Background of the Invention" and "Description of the Invention" sections of the patent describe certain elements as generally known in the art, these are presented as common knowledge or existing challenges rather than specific, citable prior art documents. For instance, the patent acknowledges the general knowledge of:

• The use of silicon wafers as central substrates for solar cells.
• Various materials for electrically passivating interface layers, such as thermally grown silicon oxide, PECVD deposited silicon nitride, intrinsic amorphous silicon, aluminum oxide, aluminum nitride, phosphorus nitride, and titanium nitride.
• Methods for reducing carrier recombination and forming high-low or p-n junctions through the diffusion of doping atoms.
• The concept of heterojunction cells using intrinsic amorphous silicon followed by doped amorphous silicon layers.
• General deposition methods like PECVD, APCVD, LPCVD, PVD, and plating.
• The capability of thermal treatment to convert amorphous silicon layers into polycrystalline silicon layers.
• Standard metallization techniques for electrodes.

However, the independent Claim 1 of US 9,130,074 describes a method that integrates specific thermal treatment steps (at least 500°C) to simultaneously achieve multiple outcomes: crystallization of an amorphous silicon-containing compound into a polycrystalline film, enhancement of the film's optical transmissivity, activation of doping atoms, and diffusion of dopant atoms into the silicon wafer to form a p-n junction or high-low junction. The patent explicitly presents these combined functions of the thermal treatment on an amorphous, silicon-containing compound as novel aspects of the "present invention" in its summary and detailed description.

Without specific prior art references that individually or collectively disclose these precise combinations of layers, materials, and, critically, the multifunctional thermal treatment presented as an aspect of the invention, it is not possible to identify combinations of prior art references from the provided text that would render Claim 1 obvious. The patent itself does not disclose a prior art combination that achieves all the recited elements, particularly the integrated functions of the thermal treatment step as claimed.