LOW DAMAGE AND RESIDUE-FREE DRY-ETCHING OF 6H-SIC USING ELECTRON-CYCLOTRON-RESONANCE PLASMA

Dry etching-induced surface damage and contamination on SiC have been investigated for electron cyclotron resonance (ECR) plasma etching and conventional reactive ion etching (RIE) using a CF4/O-2 gas mixture. Auger electron spectroscopy shows that there is no residue on the ECR etched surfaces and sidewalls of the etched structures. In contrast, t he conventional RIE process leaves residues containing large amounts o f Al, F, and O impurities on the surfaces and the etched sidewalls. Pd Schottky diodes on the ECR etched surface show a near-ideal diode cha racteristics with ideality factor of 1.06, indicating a good surface q uality. Pd Schottky diodes on the a conventional RIE etched surface, h owever, have a substantially reduced barrier height from 1.05 eV for t he as-grown sample to 0.64 eV and a high ideality factor of 1.27, indi cating a substantially damaged surface. Significant foe-carrier reduct ion is observed in the RIE etched sample. (C) 1995 American Institute of Physics.