An improved non-alloyed ohmic contact Cr/Ni/Au to n-type GaN with surface treatment

Abstract

The Cr/Ni/Au non-alloyed ohmic contact resistance on n-type GaN is obtained by chemical surface treatment of n-type GaN films following the laser lift-off of the sapphire substrate. The effects of n-GaN surface treatments on the metal/GaN interface were studied using x-ray photoelectron spectroscopy. Nitrogen vacancies at the n-type GaN surface are therefore produced and act as donors for electrons, improving the non-alloyed ohmic contact resistance induced by the reduction in native oxygen by the surface treatment of chemical solutions. In addition, the n-GaN surface treatment reduces the forward voltage (Vf) of the vertical LEDs.