Epitaxial growth

Which method is used to grow thick GaN layers quickly to make free-standing GaN substrates?

  1. AALD (atomic layer deposition)
  2. BHVPE (hydride vapor phase epitaxy)
  3. CThermal oxidation
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Answer: B. HVPE (hydride vapor phase epitaxy)

HVPE grows GaN by reacting gallium chloride, formed from gallium and hydrogen chloride, with ammonia, achieving high growth rates of tens to hundreds of micrometers per hour. Growing thick GaN and removing it from the substrate produces free-standing GaN substrates.

  • A. ALD grows one atomic layer at a time and is unsuited to thick layers.
  • B. Correct. It grows thick GaN at high rates.
  • C. Thermal oxidation forms silicon oxide films.
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More Epitaxial growth questions

  1. Which is closest to the density of threading dislocations, which run up to the film surface, in GaN grown on sapphire?
  2. In bipolar transistors and similar devices, what is the main purpose of a heavily doped layer (buried layer) beneath the epitaxial layer?
  3. Which is closest to the typical growth temperature for SiC epitaxy (CVD)?
  4. Which type of reactor is mainstream for silicon epitaxial growth on 300 mm wafers?
  5. In heteroepitaxy of materials with very different lattice constants, what is the purpose of inserting a "graded buffer layer" whose composition changes gradually?