Physics of Semiconductor Devices

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Schottky diode

Possible oral exam questions about Schottky diodes:

Draw the band diagram (valence band, conduction band, Fermi energy) for a Schottky diode with a

  • n doped semiconductor
  • p doped semiconductor

at zero bias. Assume that interface states pin the Fermi energy to the middle of the semiconducting gap at the interface.

Indicate where the depletion region is and explain why it is depleted.

Draw the charge density, the electric field, and the electrostatic potential of a Schottky diode.

Draw the band diagram in forward bias. Of the current transport mechanisms we discussed in course (drift, diffusion, thermionic emission, and tunneling) which are dominant in a forward biased Schottky diode. Which are dominant in a reverse biased diode? Why?

Draw the current voltage characteristics for a Schottky diode. What is the formula? How is this formula derived? Why is the nonideality factor about 1 for a Schottky diode?

Compare a Schottky diode to a pn-diode. In which applications do Schottky diodes perform better than pn-diodes?