Evaluation of metal/indium-tin-oxide for transparent low-resistance contacts to p-type GaN

摘要

In search of a better transparent contact to p-GaN, we analyze various metal/indium-tin-oxide (ITO) (Ag/ITO, AgCu/ITO, Ni/ITO, and NiZn/ITO) contact schemes and compare to Ni/Au, NiZn/Ag, and ITO. The metal layer boosts conductivity while the ITO thickness can be adjusted to constructive transmission interference on GaN that exceeds extraction from bare GaN. We find a best compromise for an Ag/ITO (3 nm/67 nm) ohmic contact with a relative transmittance of 97percent of the bare GaN near 530 nm and a specific contact resistance of 0.03 OMEGA (centre dot) cm~(2). The contact proves suitable for green light-emitting diodes in epi-up geometry.