Investigation of Contact Metal Stacks for Submicron GaN HEMT

摘要

Encapsulated Ti/Al/Ni/Au metal stack for Ohmic contacts and TaN vs. Ni for Schottky contacts for submicron GaN HEMTs have been investigated. The results show that the composition of the SiN_x encapsulation layer is a dominant factor, affecting metal morphology, edge definition and e-beam lithography alignment mark detection. The results show that TaN can be used as a Schottky gate at very high temperature applications, but Ni has superior barrier height and it is stable at 300℃.