Evaluation of damage induced by inductively coupled plasma etching of 6H-SiC using Au Schottky barrier diodes

Surface damage of 6H-SiC induced by inductively coupled plasma (ICP) etching with a CF4/O-2 gas mixture has been evaluated by Au Schottky barrier diodes formed on the etched surfaces. The influence of substrate de bias has been studied. It is found that there is an optimum de bias for ICP etching. Under the optimum de bias voltage, Schottky barrier diodes on the etched surface are of high quality and are comparable with diodes formed on the control sample, indicating that a very low damage and low contamination surface is obtained after etching. A deterioration of etched surface has been observed for both smaller and larger de biases compared to the optimum bias in term of characteristics of Schottky diodes. Explanations are provided for the observed dependence of Schottky barrier diode characteristics on the substrate de bias. (C) 1998 American Institute of Physics.