Excellent Schottky Characteristics of Indium-tin-oxide Contact to n-type GaN

Abstract

Abstract-Excellent Schottky characteristics of indium-tinoxide (ITO) contact formed on n-type GaN (n-GaN) were demonstrated. The post-thermal annealing of ITO contact sputtered on n-GaN led to a significant improvement in the Schottky characteristics, particularly pronounced in the air ambient than nitrogen ambient, e.g., the rectification ratio (measured at ± 1.0 V) was increased from 4.9 to 4240 after an optimized post-thermal annealing. Thermionic field emission model applied to the forward current-voltage curves of the ITO/n-GaN Schottky diodes also exhibited that the Schottky barrier height could be as high as 0.93 eV. The observed excellent Schottky characteristics with postthermal annealing are attributed to the improved ITO crystallinity as verified by glancing X-ray diffraction method