Review of ohmic contacts to compound semiconductors

A solid state switch is required to pass very high current densities, J, upon demand. Electrical access to the switch is through ohmic contacts which interface the device to the external circuit. Thus, accurate characterization of these contacts is essential in the design of the switch. Most work to date has centered around the electrical characteristics of switches, in particular the resistance R, and a reduction in joule (J2R) heating. In this paper we consider both the electrical characteristics and the thermal stability of the ohmic contacts on the operation of solid state switches. Thermal stability is important due to the inherent heating of the switch during its on time. Further, some applications will place switches in environments requiring operation at high temperature. The paper describes the present status of ohmic contacts to GaAs and InP.