Ti/Ni ohmic contacts to n-type gallium nitride

We investigated Ti and Ni based contacts to find a metallization which is convenient for a self aligned technology such that the ohmic contact can be used as a mask at GaN plasma etching for light emitter fabrication. The contacts with lowest value of Rcont = 1.1 × 10−5 Ω cm−2 at current densities up to 30 kA cm−2 were formed on GaN layers having a donor concentration of ~1 × 1018 cm−3. They demonstrated good thermal and chemical stability and were used as a mask for GaN etching in a CCl2F2/Ar plasma.