Electrical Properties of 4H-SiC Thin Films Reactively Ion-Etched in SP_6/O_2 Plasma

摘要

The electrical properties of single crystal 4H-SiC thin films have been investigated using the Au-Schottky barrier diodes (SBD's) on the etched surfaces in SF_6/O_2 plasma with reactive ion etching mode. It is found by atomic force microscopy (AFM) that the root-mean-square (RMS) roughness of etched surfaces was reduced from 8.5 A to 5.7 A as oxygen concentration in the reactant gases increased from 0% to 50 %. From the Auger electron spectroscopy (AES), it was revealed that the reactive ion etching (RIE) etched surfaces had the residual species such as fluorine and oxygen regardless of etching conditions. The I-V characteristics of SBD's showed that an increase of oxygen content in the SF_6/O_2 feeding gas mixtures made an improvement in the reverse-bias performance of Schottky diodes in spite of such residual contaminants on the surface.