Ohmic contacts in GaAs

Abstract

Ohmic contacts of n-type GaAs can be reproducibly made to exhibit specific contact resistivities less than 1 × 10-6 Ω - cm-2. To do this requires an understanding of the physics involved, a knowledge of the history of previous treatment of the GaAs wafer surface, and processing techniques which are compatible with precisely controlled donor impurity site location determination. The present paper correlates the electrical effects observed in several significant recent developments with theory and interface chemistry to provide workers in the field with a physical understanding of what is essential for reproducible, effective, and reliable ohmic contacts. © 1980.