Samsung Electronics Co Ltd v. Acorn Semi LLC

1. Case Identification

• Case #: IPR2020-01204
• Patent #: 8,766,336
• Filed: June 29, 2020
• Petitioner(s): Samsung Electronics Co., Ltd.
• Patent Owner(s): Acorn Semi, LLC
• Challenged Claims: 1-16 and 65-80

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 ’336 patent relates to electrical junctions between a metal and a semiconductor. The invention purports to reduce the specific contact resistance of the junction by disposing a thin interface layer, comprising a metal oxide, between the contact metal and a group IV semiconductor to reduce the height of the Schottky barrier.

3. Grounds for Unpatentability

Ground 1: Anticipation over Grupp - Claims 1-16 and 65-80 are anticipated by Grupp under 35 U.S.C. §102(b).

• Prior Art Relied Upon: Grupp (Patent 7,176,483).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner’s anticipation argument hinges on its assertion that the ’336 patent is not entitled to its claimed priority date of August 12, 2002. Petitioner argued that the ’336 patent’s parent applications fail to provide adequate written description and enablement for several key limitations, resetting the critical date to the patent’s actual filing date of November 28, 2012. This makes Grupp, issued in 2007, valid prior art. Petitioner contended that Grupp, a continuation-in-part of one of the ’336 patent’s own parent applications, explicitly discloses every limitation of the challenged claims. This includes teaching a metal-semiconductor junction with a metal oxide (e.g., TiO2) interface layer, the use of such a junction for a transistor’s source or drain, the configuration of the layer to reduce the Schottky barrier, and achieving specific contact resistance values well within the claimed ranges (e.g., "less than or equal to approximately 10 Ω-µm²"). Grupp also allegedly discloses the specific semiconductor materials and structures recited in dependent claims, such as n-type doping and the list of group IV semiconductors including carbon. Because Grupp discloses features not described in the ’336 patent's parent applications (e.g., carbon semiconductors, a stack of metals), Petitioner argued it anticipates all challenged claims.

4. Key Technical Contentions (Beyond Claim Construction)

• Priority Date Challenge: Petitioner’s central technical argument was that the challenged claims are not entitled to any priority date earlier than the patent's filing date (November 28, 2012), making Grupp available as prior art. This argument was based on two alleged deficiencies in the chain of parent applications:
  • Lack of Enablement: Petitioner asserted that the parent applications fail to enable the full scope of the claimed specific contact resistance limitations. The claims recite an upper bound on resistance (e.g., "less than or equal to approximately 10 Ω-µm²") but no lower bound, thereby encompassing a range down to approximately zero. Petitioner argued the shared specification provides no working examples or guidance on how to achieve these ultra-low resistance values, rendering the full scope of the claims not enabled.
  • Lack of Written Description: Petitioner contended that the parent applications fail to provide written description for several generic limitations that were broadened during prosecution. Key examples included:
    • "metal oxide": The parent applications allegedly only disclosed a single species, TiO2, which is insufficient to support the entire genus of "metal oxide" interface layers.
    • "group IV semiconductor": The disclosed examples (e.g., Si, SiGe) allegedly do not represent the full genus, failing to disclose key members like carbon, which has a significantly different bandgap from the range described in the specification.
    • "a stack of metals": The parent applications allegedly described only a single metal or alloy layer, not a "stack" of distinct metal layers as claimed.

5. Arguments Regarding Discretionary Denial

• §325(d) - Same or Substantially Same Art or Arguments: Petitioner argued that denial under §325(d) was improper because the U.S. Patent and Trademark Office had not previously considered the patentability of the challenged claims in view of the specific arguments presented. Although Grupp was cited in information disclosure statements during prosecution, Petitioner contended that no Examiner ever applied Grupp against any claim of the ’336 patent or its parents. Crucially, the Examiner never addressed the dispositive priority date issue that forms the basis of the petition, and therefore never considered Grupp as prior art.
• §314(a) - Fintiv Factors: Petitioner argued that the Fintiv factors governing discretionary denial in view of a parallel district court proceeding weighed in favor of institution. Key arguments included:
  • The district court (E.D. Tex.) has shown a willingness to grant stays after the Board institutes an inter partes review (IPR), even in advanced cases, which would conserve judicial resources and avoid overlap.
  • The scheduled trial date in the parallel litigation was not fixed and was subject to change, reducing its weight as a factor.
  • Petitioner stated its willingness to cease asserting Grupp against the challenged claims in the district court if the IPR was instituted, further mitigating any overlap.
  • The petition raised a strong, compelling merits case based on a previously unaddressed priority date challenge.

6. Relief Requested

• Petitioner requests institution of an IPR and cancellation of claims 1-16 and 65-80 of the ’336 patent as unpatentable.