Anisotropic and Selective Reactive Ion Etching of SiC in CHF3 and Oxygen Plasma

Abstract

ABSTRACTThe use of CHF3 plus oxygen plasma to achieve selective and anisotropic patterning of SiC thin films in the reactive ion etching (RIE) mode is reported. Experiments were performed using various levels of oxygen percentage (from zero to 90%), pressure (from 20 to 300 mTorr) and power (from 100W to 350W). Anisotropic etching of SiC with a vertical-to-lateral etch ratio in excess of 8:1 was measured for a CHF3 + 75%02 mixture at 20mT pressure and 200W RF power. Under these conditions, the SiC etch rate was measured to be 400 A/min and the selectivity over Si was approximately 2.2:1. The effect of the cathode DC potential and emission intensity of various species in the plasma on the SiC and Si etch rates is considered.