High-Temperature Reliable Ni2Si-Based Contacts on SiC Connected to Si-Doped Al Interconnect via Ta/TaN Barrier

Abstract

One major problem when operating SiC power devices at a junction temperature of more than 200°C is the pronounced degradation of the Ni2Si-based ohmic contacts caused by interaction with the Al interconnect. In this paper, measures against such trouble and their effectiveness are discussed. Two measures highly compatible with Si device technology have been devised and experimentally implemented: (1) insertion of a Ta/TaN barrier metal between the Al interconnect and the Ni2Si contacts; (2) use of 1 wt% Si-doped Al as the interconnect. A failure lifetime of more than 12000 hours has been attained in a temperature range up to 385°C.