Low resistance Ti/Al/Ni/Au Ohmic contact to (NH4)2Sx treated n-type GaN for high temperature applications

摘要

Low resistance Ti/Al/Ni/Au Ohmic contact to (NH4)2Sx treated n-type GaN has been studied in the temperature range from 25 · ·to 600· · It is found that the specific contact resistivity pc of the sample treatedwith (NH4)2Sx solution for 5 min at 90· ·decreases with increasing measuring temperature,while the ρc of thesample treated with (NH4)2Sx,solution for 25 min at 90· · increases with increasing measuring temperature. Excellent agreement with the "5min-treated" sample can be obtained by the field emission model with an average Schottky barrier height (SBH) ΦB=1.05eV. Meanwhile,a field emission model with a temperature-dependent effective SBH is suggested to be responsible for the "25min-treated" sample in which metal/semiconductor (MS) interface potential pinch-off may occur.