Electrical characteristics of n-GaN Schottky contacts on cleaved surfaces of free-standing substrates: Metal work function dependence of Schottky barrier height

摘要

We report the electrical characteristics of Schottky contacts with nine different metals (Ag, Ti, Cr, W, Mo, Au, Pd, Ni, and Pt) formed on clean m-plane surfaces by cleaving freestanding GaN substrates, compared with these of contacts on Ga-polar c-plane n-GaN surfaces grown on GaN substrates. The n-values from the forward current-voltage (I-V) characteristics are as good as 1.02-1.18 and 1.02-1.09 for the m-and c-plane samples, respectively. We found that the reverse I-V curves of both samples can be explained by the thermionic field emission theory, and that the Schottky barrier height of the cleaved m-plane contacts shows a metal work function dependence. (c) 2018 The Japan Society of Applied Physics.