Reliability assessment of Ti/TaSi2/Pt ohmic contacts on SiC after 1000 h at 600 °C

Abstract

We report the result of the development and analysis of Ti/TaSi2/Pt high temperature ohmic contact metallizations on n-type 4H– and 6H–SiC that can successfully withstand 1000 h of 600 °C thermal treatment in air. Understanding the reaction kinetics and dominant failure mechanisms enabled metal thicknesses in the multilayer stack to be optimized, thereby providing stable specific contact resistivity in the range of 1–6×10−5 Ω cm2 on the n-type 4H–SiC and 6H–SiC epilayers throughout the duration of heat treatment in air. The deleterious effects of platinum in a platinum-rich silicide and the benefits in a platinum Si-rich silicide were identified within the multilayer system. A high temperature ohmic contact figure of merit is proposed as a reliability benchmark and calculated for the contacts to 4H– and 6H–SiC.