Effects of Annealing on Electrical Characteristics and Current Transport Mechanisms of the Y/p-GaN Schottky Diode

Abstract

This study investigates the effects of annealing on the electrical properties and current transport mechanism of Y/p-GaN Schottky barrier diodes (SBDs). We found no significant change in the surface morphology of the Y Schottky contacts during the annealing process. The Schottky barrier height (SBH) of the as-deposited Y/p-GaN SBD was estimated to be 0.95 eV (I–V)/1.19 eV (C–V). The SBH increased upon annealing at 400°C and 500°C, and then decreased slightly with annealing at 600°C. Thus the maximum SBH of the Y/p-GaN SBD was achieved at 500°C, with values of 1.01 eV (I–V)/1.29 eV (C–V). In addition, the SBH values were estimated by Cheung’s, Norde, and Ψs-V plots and were found to be in good agreement with one another. Series resistance (RS) values were also calculated by I–V, Cheung’s, and Norde functions at different annealing temperatures, with results showing a decrease in the interface state density of the SBD with annealing at 500°C, followed by a slight increase upon annealing at 600°C. The forward-bias current transport mechanism of SBD was investigated by the logI–logV plot at different annealing temperatures. Our investigations revealed that the Poole–Frenkel emission mechanism dominated the reverse leakage current in Y/p-GaN SBD at all annealing temperatures.