Finding the optimum Al-Ti alloy composition for use as an ohmic contact to p-type SiC

Alloys of aluminum and titanium have been successfully used to form low resistance ohmic contacts to p-type SiC. While the 90 wt.% Al alloy has been studied extensively, the literature does not reveal any work which indicates whether the 90/10 or any other alloy composition is the best alloy for use as an ohmic contact material to p-SiC. This work systematically looks at four different Al-Ti alloy compositions in an attempt to decide which alloy if any is superior as an ohmic contact material. The alloy compositions that were studied were chosen by examining the binary Al-Ti phase diagram and choosing specific phases prior to reaction with the SiC. It will be shown that only alloys which have some amount of a liquid phase present at the anneal temperature will form an ohmic contact to p-type SiC. (C) 2002 Elsevier Science Ltd. All rights reserved.