Epitaxial growth

Compared with thermal diffusion, what is an advantage of adding dopants during epitaxial growth?

  1. AIt is always cheaper
  2. BIt is easier to create abrupt changes in concentration with depth
  3. CUniform concentration cannot be achieved
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Answer: B. It is easier to create abrupt changes in concentration with depth

In thermal diffusion, dopants spread from the surface inward, so concentration changes gradually. In epitaxial growth, switching the amount of dopant gas during growth changes the concentration layer by layer, creating abrupt concentration changes and structures with heavily doped layers buried inside.

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More Epitaxial growth questions

  1. In advanced CMOS processes, why is it necessary to lower the temperature of silicon and SiGe epitaxial growth?
  2. Which polytype is mainly used for SiC power devices?
  3. In MBE, which technique observes growth in situ by directing an electron beam at the surface at a grazing angle and examining the diffraction pattern?
  4. What is the origin of the word "epitaxy"?
  5. What is the typical thickness range of the epitaxial layer on silicon epi wafers for LSIs and power devices?