Electrical and photoelectric properties of Au-SiC Schottky barrier diodes

Ultraviolet-sensitive diodes fabricated by gold evaporation on epitaxial 6H-SiC layers with a non-compensated donor density of similar to 10(17) cm(-3) are described. The reverse current at low bias is shown to be governed by charge generation in the space charge region and at high bias - by tunneling and avalanche processes. The parameters required for calculation of the photoelectric quantum efficiency and responsivity spectrum of the diodes have been determined. It is shown that limitations in the Au-SiC diode responsivity are caused by the small hole diffusion length (similar to 10(-5) cm) and the low optical transmittance of the metal layer and the metal-semiconductor interface. (C) 1998 Elsevier Science Ltd. All rights reserved.