Silicon wafers

What is the purpose of using bulk microdefects (BMDs), formed by oxygen precipitation inside CZ wafers?

  1. ATo use them as gettering sites that capture metal impurities
  2. BTo make the wafer emit light
  3. CTo weaken the wafer
Show answer and explanation

Answer: A. To use them as gettering sites that capture metal impurities

Oxygen in CZ wafers forms precipitates inside the wafer during heat treatment (BMDs, bulk microdefects). These precipitates and the strain around them capture metal impurities, so they are used for intrinsic gettering, keeping metal contamination away from the device region at the surface.

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More Silicon wafers questions

  1. Heat treatment of a wafer diffuses oxygen out from near the surface, creating a low-defect layer at the surface where devices are made. What is this layer called?
  2. What is the purpose of the laser mark (ID mark) inscribed on the front or back of a wafer?
  3. Which polishing method is common for 300 mm wafers?
  4. What is a used monitor wafer called after its surface films are removed and it is repolished for reuse?
  5. Which method is used to measure wafer resistivity without contact?