Electrical characteristics of Au/Ni Schottky diodes on cleaved m-plane surfaces of free-standing n-GaN substrates

We report electrical characteristics of 12 Ni Schottky contacts formed on an m-plane surface, which is a cleaved side surface of a c-plane freestanding n-GaN wafer. We observed a variety of distributions of surface steps with heights up to 5 nm in the contact area. The Schottky barrier heights obtained from current-voltage, capacitance-voltage, and photoresponce results distribute in a small range of 0.67-0.79 eV. The n-value is as good as 1.01 to 1.04. Independent of the step height, the barrier height and n-value variations are nearly absent. One possible reason for this is that the step facets consist of an m-plane. We found that the cleaving method can be utilized to form Schottky contacts on m-plane n-GaN surfaces in order to reveal the basic characteristics. (C) 2016 The Japan Society of Applied Physics