Silicon wafers

Which method selectively and shallowly etches defect regions so that dislocations and stacking faults in silicon can be observed with an optical microscope?

  1. AReactive ion etching
  2. BSelective (defect) etching such as Secco etching
  3. CSacrificial layer etching
Show answer and explanation

Answer: B. Selective (defect) etching such as Secco etching

Selective etching uses solutions (such as Secco or Wright etchants) that etch the strained regions around defects faster than their surroundings, revealing the defects as pits. Counting the pits under an optical microscope gives the crystal defect density.

  • A. Reactive ion etching is dry etching for patterning.
  • B. Correct. Defects are selectively etched to make them visible.
  • C. Sacrificial layer etching is a MEMS step for releasing structures.
Practice this topic Back to topic

More Silicon wafers questions

  1. In CZ crystals, what are the periodic, striped variations in dopant or oxygen concentration caused by fluctuations such as temperature at the growth interface called?
  2. Along which crystal planes does single-crystal silicon cleave most easily?
  3. Which method is most widely used to produce single-crystal silicon for LSIs?
  4. Which wafer diameter is currently mainstream in leading-edge logic and memory production lines?
  5. Which is a characteristic of single-crystal silicon made by the FZ (floating zone) method?