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

Abstract

Excellent Schottky characteristics of indium-tin-oxide (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 post-thermal annealing are attributed to the improved ITO crystallinity as verified by glancing X-ray diffraction method Keywords-indium tin oxide; Schottky contact; thermal annealing; thermionic field emission.