Oxidation and diffusion

How does the diffusion coefficient of dopants in silicon depend on temperature?

  1. AIt does not depend on temperature
  2. BIt decreases as temperature rises
  3. CIt increases exponentially as temperature rises
Show answer and explanation

Answer: C. It increases exponentially as temperature rises

The diffusion coefficient follows the Arrhenius form D = D0 exp(−Ea / kT) and increases exponentially with temperature. Because small temperature differences greatly change diffusion depth, temperature must be controlled precisely in diffusion and heat-treatment steps.

Practice this topic Back to topic

More Oxidation and diffusion questions

  1. Which method is mainly used for device isolation in scaled LSIs?
  2. Once the oxide has become sufficiently thick in thermal oxidation, how does its thickness relate to oxidation time?
  3. Why does oxide on silicon appear in different colors depending on its thickness?
  4. Which equipment is commonly used to thermally oxidize many wafers at once?
  5. In thermal diffusion, what is the step called that drives dopants deeper after a fixed amount has been introduced at the surface?