The barrier height and interface effect of Au-n-GaN Schottky diode

Schottky barrier contact using Au and ohmic contact using Al were made on n-GaN grown by hydride vapour phase epitaxy. The diodes were characterized in the range 77-373 K. Under forward bias, the ideality parameter n=1.04 and the threshold voltage is 1.1 V. The reverse bias leak current is below 10 -9 A on a reverse bias of -10 V. The temperature-dependence of the I-V characteristics shows two regimes of forward current transport: one at low voltage governed by thermionic emission and the high-voltage regime due to spatial inhomogeneities at the metal-semiconductor interface. The barrier height phi B and the electron affinity X S were determined to be 0.91 and 4.19 eV, respectively, by I-V measurement; and 1.01+or-0.02 and 4.09 eV, respectively, by C-V measurement. The results have been discussed.