{
  "patent_number": "US 5563422",
  "country": "US",
  "title": "How Nichia Created the First Practical Blue LED Electrodes",
  "original_title": "Gallium nitride-based III-V group compound semiconductor device and method of producing the same",
  "summary": "A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable.",
  "what_it_does": "This patent details the construction of a light-emitting diode (LED) using gallium nitride, specifically focusing on how to create reliable electrical connections. It describes a 'second electrode' made of nickel or a nickel-gold alloy that sits on top of the p-type semiconductor layer. To ensure this connection works properly, the patent specifies that the electrode must be annealed—heated to at least 400 degrees Celsius—to form an ohmic contact, which allows electricity to flow easily into the semiconductor. This was critical because, without this specific metal-to-semiconductor interface, the device would not efficiently inject the current required to produce light.",
  "what_it_does_not_cover": [
    "Does not cover the underlying growth process of the gallium nitride crystal itself.",
    "Does not cover LEDs made from materials other than gallium nitride-based III-V compounds.",
    "Does not cover electrode materials that do not utilize nickel or nickel-gold combinations as specified.",
    "Does not cover non-ohmic contact methods that rely on different electrical physics."
  ],
  "filed": "1994-04-28",
  "granted": "1996-10-08",
  "expires": "2014-04-28",
  "status": "expired",
  "holder": "Nichia Chemical Industries Ltd",
  "holder_url": "https://patentbrief.org/company/nichia-chemical-industries-ltd",
  "inventors": [
    {
      "name": "Shuji Nakamura",
      "url": "https://patentbrief.org/inventor/shuji-nakamura"
    },
    {
      "name": "Takao Yamada",
      "url": "https://patentbrief.org/inventor/takao-yamada"
    },
    {
      "name": "Masayuki Senoh",
      "url": "https://patentbrief.org/inventor/masayuki-senoh"
    },
    {
      "name": "Motokazu Yamada",
      "url": "https://patentbrief.org/inventor/motokazu-yamada"
    },
    {
      "name": "Kanji Bando",
      "url": "https://patentbrief.org/inventor/kanji-bando"
    }
  ],
  "times_cited": 251,
  "tags": [
    "semiconductors",
    "consumer_electronics",
    "energy"
  ],
  "abstract": "A gallium nitride-based III-V Group compound semiconductor device has a gallium nitride-based III-V Group compound semiconductor layer provided over a substrate, and an ohmic electrode provided in contact with the semiconductor layer. The ohmic electrode is formed of a metallic material, and has been annealed.",
  "url": "https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride",
  "markdown_url": "https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride/md",
  "google_patents_url": "https://patents.google.com/patent/US5563422",
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}