Long-term thermal stability of Ti/Al/Pt/Au Ohmic contacts to n-type GaN

Abstract
We present a study of the long-term thermal stability and low specific contact resistance of Ti/Al/Pt/Au multilayer contacts to n-type GaN. The Ohmic performance can be maintained up to 60 and 540 min for thermal annealing at 950 and 850 °C, respectively, and even longer than 600 min for thermal annealing at 750 °C. By comparing the specific contact resistances for Ti/Al/Pt/Au and Ti/Al/Au Ohmic contacts to n-type GaN, the long-term thermal stability may be deduced as due to the contribution of the Pt barrier for preventing Au penetration.