Au/Ti/Al contacts to SiC for power applications: electrical, chemical and thermal properties

A new Au/Ti(70%)/Al(30%) composition has been proposed and investigated as an ohmic contact to p-type SiC. The dependence of the resistivity on the annealing conditions has been studied at temperatures ranging from 700 /spl deg/C to 950 /spl deg/C. The lowest contact resistivity of 1.40 /spl times/ 10/sup -5/ /spl Omega/.cm/sup 2/ is achieved after annealing at 900 /spl deg/C. The study of the thermal properties determines the contact stability during the ageing at temperatures of 500-700 /spl deg/C, operating temperatures up to 450 /spl deg/C and current densities of 10/sup 3/ A/cm/sup 2/. XPS depth analysis of annealed and aged contacts has been performed to understand the origin of the ohmic properties and the thermal and power stability observed.