Rothschild v. Cree, Inc.

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Gertrude Neumark Rothschild (New York)
  • Defendant: Cree, Inc. (North Carolina)
  • Plaintiff’s Counsel: Sidley Austin Brown & Wood LLP
• Case Identification: 1:05-cv-05939, S.D.N.Y., Filing Date 06/27/2005
• Venue Allegations: Venue is alleged based on Defendant’s systematic and continuous business activities in the district, including sales, marketing, website availability, participation in trade shows, and deriving substantial revenue from New York.
• Core Dispute: Plaintiff alleges that Defendant’s Light Emitting Diodes (LEDs) and Laser Diodes (LDs) are created using patented processes for doping wide band-gap semiconductors.
• Technical Context: The technology relates to semiconductor manufacturing, specifically processes intended to overcome longstanding difficulties in creating efficient, low-resistivity materials for LEDs and LDs that emit light in the green or other high spectral ranges.
• Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the patents-in-suit.

Case Timeline

Date	Event
1988-08-15	’499 Patent Priority Date
1988-08-22	’618 Patent Priority Date
1990-02-27	’618 Patent Issue Date
1993-10-12	’499 Patent Issue Date
2005-06-27	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 4,904,618 - Process for Doping Crystals of Wide Band Gap Semiconductors, issued February 27, 1990

The Invention Explained

• Problem Addressed: The patent’s background section describes the difficulty in manufacturing "well-conducting" p-type wide band-gap semiconductors, such as zinc selenide (ZnSe), which is necessary for creating effective p-n junctions for electronic devices like LEDs (’618 Patent, col. 2:20-30).
• The Patented Solution: The invention proposes a method of "non-equilibrium impurity incorporation" to increase the concentration of a desired dopant beyond its normal solubility limit. This is achieved by introducing the desired "primary dopant" (e.g., nitrogen) along with a "secondary compensating" dopant (e.g., lithium). The presence of the secondary dopant increases the amount of the primary dopant the crystal can absorb. Subsequently, the more mobile secondary dopant is preferentially removed, typically by heating, leaving behind a high, non-equilibrium concentration of the desired primary dopant, thereby improving the material's conductivity (’618 Patent, Abstract; col. 2:32-49).
• Technical Importance: This technique was asserted to make it "commercially feasible to produce LEDs and LDs in green or other high spectral ranges," which had previously been a significant challenge in the industry (Compl. ¶¶ 14, 20).

Key Claims at a Glance

• The complaint asserts infringement of "one or more claims" of the ’618 Patent (Compl. ¶22). Independent claim 1 is representative of the core process.
• Independent Claim 1 requires:
  • A process for the non-equilibrium incorporation of a dopant into a crystal of a wide band gap semiconductor.
  • Treating the crystal in the presence of first and second compensating dopants of different mobilities.
  • Introducing substantially equal amounts of the two dopants into the crystal, such that the concentration of the less mobile dopant exceeds its normal solubility.
  • Heating the crystal to preferentially remove the more mobile of the two dopants.
  • Thereby leaving a non-equilibrium concentration of the less mobile dopant in the crystal.
• The complaint's general allegation preserves the right to assert other claims, including dependent claims.

U.S. Patent No. 5,252,499 - Wide Band-Gap Semiconductors Having Low Bipolar Resistivity and Method of Formation, issued October 12, 1993

The Invention Explained

• Problem Addressed: The patent addresses the problem of "compensation" in wide band-gap semiconductors, where unintended impurities (e.g., donor impurities in p-type material) are present and increase the material’s electrical resistivity, degrading the performance of devices like LEDs (’499 Patent, col. 1:41-51).
• The Patented Solution: The invention claims a method to reduce this unwanted resistivity by using atomic hydrogen. After a semiconductor is doped, atomic hydrogen is introduced into the material to "neutralize" the problematic compensating impurities, rendering them electrically inactive. An alternative embodiment involves introducing the desired dopant and hydrogen together, then later removing the hydrogen to leave a "compensation free" material (’499 Patent, Abstract; col. 2:4-11).
• Technical Importance: This process offers a method to create semiconductors with low resistivity on both the p-type and n-type sides of a junction, which is critical for fabricating high-performance optoelectronic devices from wide band-gap materials (’499 Patent, col. 1:5-13).

Key Claims at a Glance

• The complaint asserts infringement of "one or more claims" of the ’499 Patent (Compl. ¶28). Independent claim 22 is representative of the core method.
• Independent Claim 22 requires:
  • A method of forming a low resistivity semiconductor from a wide band-gap semiconductor substrate that has unacceptably high resistivity due to excessive compensators.
  • Introducing at least an effective quantity of atomic hydrogen into the substrate.
  • To neutralize an acceptable portion of the compensators.
• The complaint's general allegation preserves the right to assert other claims, including dependent claims.

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are Light Emitting Diodes ("LEDs") and Laser Diodes ("LDs") that are manufactured, imported, used, or sold by Defendant Cree (Compl. ¶¶ 6, 22, 28).

Functionality and Market Context

• The complaint describes LEDs as durable and efficient semiconductor devices that convert electricity into light and have gained wide acceptance in applications such as backlighting for electronics, traffic lights, and billboards (Compl. ¶¶ 11-12, 15). The complaint alleges that the patented processes enable the commercial production of LEDs and LDs in high spectral ranges, such as green, and that billions of dollars in revenue are generated annually from sales of these products (Compl. ¶¶ 17, 20).

IV. Analysis of Infringement Allegations

The complaint does not provide sufficient detail, such as a claim chart or specific descriptions of Defendant’s manufacturing processes, to conduct a detailed, element-by-element analysis of infringement. The infringement theory is presented as a general narrative.

The narrative theory for the ’618 Patent is that Defendant Cree’s process for manufacturing its LEDs and LDs includes the steps of introducing two compensating dopants of different mobilities into a semiconductor crystal and then preferentially removing the more mobile dopant, thereby directly infringing the claimed method (Compl. ¶22).

The narrative theory for the ’499 Patent is that Defendant Cree’s manufacturing process for its LEDs and LDs involves introducing atomic hydrogen into a semiconductor substrate to neutralize unwanted compensators and reduce resistivity, thereby directly infringing the claimed method (Compl. ¶28).

No probative visual evidence provided in complaint.

Identified Points of Contention

• Evidentiary Questions: The central issue for both patents will be factual and dependent on discovery. What specific manufacturing process(es) does Cree use? Does the evidence show that Cree’s process utilizes a sacrificial secondary dopant as described in the ’618 Patent, or does it use atomic hydrogen to passivate impurities as described in the ’499 Patent? The complaint provides no specific facts on these points.
• Technical Questions: A key technical question for the ’499 Patent is whether any use of hydrogen in Cree's process (e.g., as a carrier gas) performs the specific function of "neutralizing" compensators as required by the claims, or if it serves an entirely different, non-infringing purpose.

V. Key Claim Terms for Construction

For the ’618 Patent

• Term: "non-equilibrium incorporation"
• Context and Importance: This term defines the invention's core technical contribution, distinguishing it from processes that result in standard, equilibrium concentrations of dopants. Practitioners may focus on this term because its construction will determine whether only the specific two-dopant method is covered or if other techniques that achieve a supersaturated state could also fall within the claim scope.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification defines the term functionally as "the incorporation of a dopant (impurity) in excess of its equilibrium solubility at a particular temperature and concentration of compensating species" (’618 Patent, col. 2:65-col. 3:2), which could be read to cover any process achieving that result.
  • Evidence for a Narrower Interpretation: The description of the invention consistently links "non-equilibrium incorporation" to the specific two-step process of introducing two dopants and then preferentially removing one, which could support an argument that the term is limited to that disclosed mechanism (’618 Patent, col. 2:32-49).

For the ’499 Patent

• Term: "neutralize"
• Context and Importance: This term describes the action performed by the atomic hydrogen and is the central step of the claimed method. Its definition is critical because it will dictate what specific interaction between hydrogen and an impurity constitutes infringement.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The abstract and summary suggest a general effect where hydrogen is used to "neutralize compensating contaminants" without detailing a specific chemical mechanism, potentially supporting a broad reading that covers any form of electrical deactivation (’499 Patent, Abstract; col. 2:4-6).
  • Evidence for a Narrower Interpretation: The detailed description notes that when neutralizing acceptors, the introduced hydrogen "will act as a donor" (’499 Patent, col. 5:32-34). This could be used to argue that "neutralize" requires a specific electrical compensation mechanism, not merely a physical bonding or removal of the impurity.

VI. Other Allegations

Indirect Infringement

• The complaint includes conclusory allegations of contributory and induced infringement for both patents (Compl. ¶¶ 22, 28). However, it does not plead specific facts to support these claims, such as alleging that Defendant provides a material component with instructions for a third party to complete the infringing manufacturing process.

Willful Infringement

• Willfulness is alleged for both patents based on the assertion that "Defendant Cree knew of the... Patent and/or should have known about this patent in performing its due diligence" (Compl. ¶¶ 23, 29). The complaint does not allege pre-suit knowledge from specific events like a notice letter.

VII. Analyst’s Conclusion: Key Questions for the Case

1. A central issue will be one of evidentiary proof: What are the actual, specific steps of Cree’s manufacturing processes for its accused LEDs and LDs? The outcome of the case will depend almost entirely on whether discovery reveals that these processes map onto the specific steps claimed in the ’618 or ’499 patents, as the complaint itself offers no factual evidence on this point.

2. A key legal question will be one of definitional scope: Assuming some factual overlap is found, the dispute may turn on claim construction. For the ’618 Patent, can Cree’s process be said to use "compensating dopants" to achieve "non-equilibrium incorporation"? For the ’499 Patent, does any hydrogen used by Cree serve to "neutralize" impurities as the patent defines that term?

3. A third question relates to culpability: Can the Plaintiff develop evidence to support its allegation that Cree’s infringement was willful? This will require moving beyond the complaint's general "knew or should have known" allegation to show specific knowledge of the patents and a deliberate or reckless disregard of the Plaintiff's patent rights.