Investigation of degradation mechanism of Schottky diodes

摘要

Schottky diode performance is influenced by fabrication processes. We present a model to investigate the dependence of Schottky diode performance on the fabrication process. To remove the native oxide layer, the In_(0.5)-(Al_(0.66)Ga_(0.34))_(0.5)P surface was etched using a chemical solution of NH_4OH + 10H_2O for various etching times. Schottky diode performances of Schottky barrier height and ideality factor were not influenced by the etching time significantly. However, the associate breakdown voltage and leakage current were degraded by the etching time. From the transmission electron microscopy micrograph of the interface between the deposited metal and the etched In_(0.5)-(Al_(0.66)Ga_(0.34))_(0.5)P, a spiky region was found to exist, formed when the metal was inserted into the roughened surface. The degradation mechanisms of Schottky diode performances were deduced from the formation of the spiky region on the etched surface.