Analysis of the current-voltage characteristic of the Schottky diode based on free-standing GaN substrate

Abstract

The current–voltage (I–V) characteristics of Schottky diodes on free-standing GaN substrate are investigated by using electrical characterization and analytical modelling calculation. We have calculated the electrical parameters from experimental current-voltage curve by two methods: ln(I) and Cheung. So, we calculated different electrical parameters using experimental I-V curve such as saturation current, ideality factor, series resistance and barrier height. We have found from the first method, the ideality factor n (1.02), the barrier height fb (0.65 eV) and a series resistance Rs (84 Ω). From the second method, we have found, n (1.09), fb (0.79 eV) and Rs (79.58 Ω - 79.73 Ω). Using analytical approach, we plotted the theoretical curves for comparison with the experimental characteristic and also to determine the dominant current transport mechanism. The results found support an assumption that the dominant current mechanism in Au/n-GaN (free-standing substrate) Schottky diode is the thermionic current.