Invalidity dossier
US 6046464
Added 9/21/2026, 10:09:29 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 6046464 A
Title: Integrated heterostructures of group III-V nitride semiconductor materials including epitaxial ohmic contact comprising multiple quantum well
Patent number: US 6046464 A (application US08/910,891; filed 1997-08-13; granted/publication date 2000-04-04)
Inventor: Jan Frederick Schetzina
Assignee: North Carolina State University (original and current assignee per the listing)
Priority date: 1995-03-29 (stated as an assumption, not a legal conclusion)
Legal status: Expired – Lifetime; anticipated expiration 2015-03-29
Purpose (per the excerpt): The invention "relates to semiconductor devices, and more particularly to semiconductor devices containing Group III-V nitride compound semiconductor materials." Those materials include AlN, GaN, InN and their ternary/quaternary alloys such as AlGaN. The text identifies two fundamental obstacles the field faced: (1) the lack of a suitable lattice-matched and preferably conducting substrate for nitride growth, and (2) the lack of a suitable ohmic contact. Bulk single-crystal nitride substrates were not then available, so nitrides were grown on sapphire or SiC and contained 10⁹–10¹¹ dislocations/cm². Insulating sapphire forces mesa etching and top-surface contacts; a conducting substrate such as SiC would allow a bottom base electrode, simplifying packaging and aiding vertical-transport devices (LEDs, laser diodes, certain transistors). A laser diode's higher above-threshold current density makes low series resistance important to avoid heating, degradation and failure.
Plain-language scope: The title indicates integrated nitride heterostructures incorporating an epitaxial ohmic contact that comprises a multiple quantum well. Classifications span nitride LED electrodes and materials (H10H20/832, H10H20/825), nitride heterojunctions (H10D62/824), and GaN-based blue lasers (H01S5/32341).
Source: https://patents.google.com/patent/US6046464/en
What the excerpt does not establish: It does not reproduce any claims, the written description's fabrication details, or the ohmic-contact/quantum-well structures; it does not identify cited prior art, and it truncates discussion (e.g., a Fig. 2 energy-band comparison). No litigation, ownership-transfer, validity, or prior-art conclusions are drawn.
Generated 10/1/2026, 10:01:51 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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