PTAB

IPR2020-01206

Samsung Electronics Co Ltd v. Acorn Semi LLC

Log In

1. Case Identification

2. Patent Overview

  • Title: Method for Depinning the Fermi Level of a Semiconductor at an Electrical Junction and Devices Incorporating Such Junctions
  • Brief Description: The ’691 patent relates to metal-semiconductor junctions that use a composite interface layer between the metal and semiconductor to control electrical properties. The interface layer includes a semiconductor oxide and a metal oxide to overcome "Fermi-level pinning," thereby improving device performance.

3. Grounds for Unpatentability

Ground 1: Anticipation over Grupp - Claims 1-4, 6, 8, 10-13, 15-20, 22, and 25-30 are anticipated by Grupp under 35 U.S.C. §102.

  • Prior Art Relied Upon: Grupp (Patent 7,176,483).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner’s central argument was that the challenged claims were not entitled to their purported 2002 priority date, making the Grupp patent, issued in 2007, valid prior art. Petitioner argued that Grupp, which shares a common ancestor with the ’691 patent, discloses every limitation of the challenged claims. For independent claim 1, Petitioner asserted Grupp teaches a structure with a semiconductor region, a metal contact, and an interface layer between them. This interface layer is described in Grupp as comprising both a passivating dielectric tunnel barrier (a semiconductor oxide like silicon oxide) and a metal oxide layer (a titanium dioxide spacer layer), which permits current flow as required by the claim. For independent claim 25, Petitioner contended Grupp discloses an electrical junction with an interface layer comprising a metal oxide separation layer (e.g., titanium dioxide) and a semiconductor oxide passivation layer, configured to provide a specific contact resistivity of less than 1 Ω-µm², a value explicitly taught by Grupp.
    • Key Aspects: The foundation of the anticipation ground is a detailed challenge to the ’691 patent’s priority claim. Petitioner argued that the parent applications fail to provide adequate written description and enablement for at least three key limitations first introduced or broadened in later applications. This failure allegedly pushes the claims’ effective priority date past Grupp’s 2007 publication date, making it anticipating prior art. This priority date challenge is detailed further in Section 5.

4. Key Claim Construction Positions

  • Petitioner argued that the claim term "specific contact resistivity," which appears in claims 18 and 25-30, should be construed as interchangeable with "specific contact resistance." Petitioner noted that the specification of the ’691 patent only discusses "specific contact resistance" and that a person of ordinary skill in the art (POSITA) would have understood the terms to be used interchangeably in this context. This construction was important for applying Grupp’s disclosure of achieving specific contact resistance values of less than 1 Ω-µm² directly to the challenged claims.

5. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner’s primary technical contention was that the challenged claims are not entitled to a priority date earlier than February 7, 2011, due to a lack of written description and enablement in the parent applications.
    • Written Description Failure: Petitioner argued that no parent application before February 2011 described the generic "metal oxide" interface layer required by all challenged claims. The earlier applications allegedly disclosed only a single species, titanium dioxide (TiO2), which was insufficient to support the entire claimed genus. Furthermore, Petitioner contended that claim 30’s "stack of metals" limitation was not described in any parent application.
    • Enablement Failure: Petitioner argued that claims 18 and 25-30, which recite a specific contact resistivity of "less than 1 Ω-µm²," were not enabled by the parent applications. Because the claim language is open-ended with no lower bound, it encompasses resistivities down to approximately zero. However, the shared specification allegedly teaches that the disclosed method has a "minimum specific contact resistance" and does not enable achieving near-zero values. This failure to enable the full scope of the open-ended claim, Petitioner asserted, limits the priority date for these claims to the filing date of the ’691 patent itself (February 19, 2016).

6. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be inappropriate under both §325(d) and §314(a) (Fintiv factors).
    • §325(d): Petitioner asserted that although Grupp was before the Examiner in an information disclosure statement (IDS) during prosecution, it was never substantively considered or applied against any claim. Petitioner argued that merely signing an IDS does not constitute the substantive review required to trigger discretionary denial under §325(d), especially since the Examiner never addressed the critical priority date issues that make Grupp applicable art.
    • §314(a) (Fintiv): Petitioner argued that the factors weigh in favor of institution. It contended that the parallel district court litigation trial date was uncertain and that the presiding court had a history of granting stays after IPR institution, minimizing concerns of duplicative efforts. Petitioner also noted its diligence, having filed the petition promptly after the Patent Owner served infringement contentions that identified 22 previously unidentified asserted claims, arguing it was reasonable to wait for such clarity before filing.

7. Relief Requested

  • Petitioner requested institution of an inter partes review (IPR), a finding that claims 1-4, 6, 8, 10-13, 15-20, 22, and 25-30 are unpatentable, and cancellation of those claims.