Epitaxial growth

What is an advantage of a wafer with a lightly doped p-type epitaxial layer grown on a p+ substrate (p/p+ epitaxial wafer)?

  1. AThe wafer becomes transparent
  2. BThe surface crystal quality is good, and CMOS latch-up is easier to suppress
  3. CEtching becomes unnecessary
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Answer: B. The surface crystal quality is good, and CMOS latch-up is easier to suppress

The epitaxial layer has few defects, improving the quality of the surface where devices are built. The low-resistance p+ substrate underneath also makes parasitic transistors less likely to turn on, helping to suppress CMOS latch-up. The heavily doped substrate also helps getter metal impurities.

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More Epitaxial growth questions

  1. Which correctly describes the critical thickness in heteroepitaxial growth?
  2. What is the main purpose of heating the wafer in high-temperature hydrogen just before silicon epitaxial growth?
  3. Why are epitaxial layers important in the fabrication of SiC power devices?
  4. In epitaxial growth by CVD, the growth rate depends strongly on temperature in the relatively low-temperature regime. Why?
  5. Which is a typical crystal defect in epitaxial layers in which the stacking sequence of atomic planes is disrupted?