Pt ohmic contact to p-type GaN with contact resistivity of 10(-4) Omega center dot cm(2) using surface treatment

Abstract

Non-alloyed ohmic contacts to p-type GaN using surface treatment prior to Pt metal deposition was investigated. For the p-type GaN with a hole concentration of 1.9 x 10(17)/cm(3), the average contact resistivity drastically decreased from 4.7 x 10(-1) Omega.cm(2) to 3.7 x 10(-4) Omega.cm(2) by the surface treatment using aqua regia. X-ray photoelectron spectroscopy analysis shows that the surface treatment using aqua regia plays a role in removing the surface oxide formed on the surface of p-type GaN, and subsequently in reducing the barrier height for holes at the interface of Pt/p-type GaN, resulting in good ohmic contacts to p-type GaN.