Epitaxial growth

Which technique, developed by Isamu Akasaki, Hiroshi Amano and colleagues to grow high-quality GaN on sapphire, first deposits a thin layer at low temperature and then grows GaN at high temperature?

  1. AChemical mechanical polishing
  2. BLow-temperature buffer layer technique
  3. CFloating zone method
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Answer: B. Low-temperature buffer layer technique

Growing GaN directly on sapphire produces rough crystals. Akasaki, Amano and colleagues first deposited a thin buffer layer of AlN or similar at low temperature and then grew GaN on top at high temperature, obtaining flat, high-quality crystals. This led to the realization of blue LEDs.

  • A. Chemical mechanical polishing is a technique for planarizing surfaces.
  • B. Correct. It uses a buffer layer deposited at low temperature.
  • C. The floating zone method makes silicon single crystals.
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More Epitaxial growth questions

  1. In a lattice-mismatched system, which growth mode grows layer by layer for the first few atomic layers and switches to island growth as strain accumulates? It is also used to make quantum dots.
  2. When silicon is grown epitaxially on a substrate with patterns such as buried layers, what is the phenomenon called in which the steps appearing on the surface are offset from the underlying pattern or distorted in shape?
  3. What is the main purpose of epitaxially growing and embedding Si:C (silicon with a small amount of carbon) in the source and drain of nMOS transistors?
  4. Which research-stage technique grows a crystal on a substrate covered with a 2D material such as graphene so that the grown film can be peeled off and the substrate reused?
  5. In epitaxial structures for GaN HEMTs, what is the main purpose of adding carbon or iron to the GaN buffer layer beneath the channel?