ABSTRACT
Ti/Al/Ti/Au contacts on AlGaN/GaN, rapid thermal annealed at temperatures ranging from 650°C to 950°C have been investigated to ascertain the effect of annealing temperature on the structural evolution of the contact. Anneals at 750°C or higher were required to produce an ohmic contact. Interfacial reaction at high temperature to form TiN is described. Samples after annealing at 950°C showed inclusions in the AlGaN layer associated with extended defects. High levels of Au, Al and N detected between the inclusion and nitride layer may indicate an insulating barrier. Results indicate the presence of an insulating barrier layer between the inclusion and the GaN. An interfacial structure consisting of Ti-rich grains was also observed.
