Deposition (CVD and PVD)

In ALD, what is the temperature range called in which self-limiting surface reactions keep the thickness per cycle constant?

  1. AGlass transition temperature
  2. BALD window
  3. CProcess margin
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Answer: B. ALD window

In ALD, too low a temperature lets precursors condense or react incompletely, while too high a temperature lets them decompose into CVD-like growth or lets adsorbed molecules desorb. The range in between, where thickness per cycle is nearly constant, is called the ALD window, and films are deposited within it.

  • A. The glass transition temperature is where glasses and polymers begin to soften.
  • B. Correct. It is the temperature range where growth is self-limiting.
  • C. Process margin refers generally to the tolerance of process conditions.
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More Deposition (CVD and PVD) questions

  1. Which is an advantage of sputtering over vacuum evaporation?
  2. Which type of CVD reactor heats only the stage holding the wafer while keeping the reactor walls cool?
  3. Which is an example of the precursors used to deposit HfO2 gate dielectrics by ALD?
  4. Which model organizes, by temperature and gas pressure, the tendency of sputtered metal films to form columnar grains with many voids at low deposition temperatures?
  5. In CVD, what is the phenomenon called in which more source gas is consumed and the deposition rate drops as the area of wafers or patterns being coated increases?