Epitaxial growth

What problem tends to occur when there is a large difference in lattice constant (lattice mismatch) between the substrate and the grown film?

  1. ACrystal defects such as misfit dislocations form
  2. BThe film always becomes amorphous
  3. CThe growth rate becomes zero
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Answer: A. Crystal defects such as misfit dislocations form

When a material with a different lattice constant is grown, strain builds up in the film, and beyond a certain thickness (the critical thickness), defects such as misfit dislocations form to relieve the strain. Because defects degrade device characteristics and reliability, techniques such as inserting buffer layers are used.

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More Epitaxial growth questions

  1. Which is a characteristic of MBE (molecular beam epitaxy)?
  2. Which gases are used as sources for silicon epitaxial growth?
  3. Which correctly describes selective epitaxial growth?
  4. What is the phenomenon called in which impurities from the substrate or elsewhere are incorporated into the growing layer through the gas phase during epitaxial growth?
  5. What is an advantage of a wafer with a lightly doped p-type epitaxial layer grown on a p+ substrate (p/p+ epitaxial wafer)?