The electrical effect on Schottky barrier diodes of Si crystallization from Al–Si metal films

Abstract

The barrier height of n‐Si Schottky contacts made with Si‐doped Al metallization is observed to vary from 0.79±0.02 V to 0.89±0.02 V after heat treatments at temperatures from 400 to 550°C. Identical diodes made with pure Al metallization have φ_B =0.68±0.02 V. The scanning electron microscope in the electron‐beam‐induced‐current mode is used to show that the upward shift in φ_B is due to a thin layer of p ‐doped Si, probably continuous, which is grown from the Al–Si metallization on the n contacts. The discretely distributed Si mesas and precipitates reported by other investigators as crystallizing out of the metallization are observed also, but are believed to play a limited electrical role.