A WSiN cap can improve the surface morphology of Ti/Al Ohmic contact to n-GaN significantly. This is because it is a conductive diffusion barrier which can help to suppress the decomposition of GaN. With WSiN cap, the edge is much sharper. However, the WSiN film may pick up Ar during the WSiN sputtering process, resulting in some surface morphology problem. This can be solved by lowering the Ar flow rate during sputtering. Auger electron spectroscopy results show that our best WSiN cap has a chemical composition of W 0.62 Si 0.14 N 0.34 .

No abstract

No abstract