Reactive ion etching (RIE) using fluorinated gases, such as admixtures of CF4 with O2, has been conducted on sputter deposited films of SiC. For comparison purposes, the same experiments with SiO2 films and Si wafers have been conducted. The influence of rf power, pressure, and O2 concentration on etch rate in CF4+O2, SF6+He, and Ar gases has been investigated. RIE mechanisms were studied using in situ monitoring of excited fluorine emission intensity and dc self‐bias at the lower electrode. Typical etch rates of Si, SiO2, and SiC are 1220, 600, and 375 A/min in CF4+4% O2; 8850, 500, and 560 A/min in SF6+50% He; and 340, 280, and 270 A/min in Ar, respectively, at P=200 W, p=20 mTorr, and 300 K. Under these conditions the dc self‐bias levels are −396 V for CF4+4% O2, −350 V for SF6+50% He, and −414 V for Ar. In both CF4+4% O2 and SF6+50% He, the etch rates of Si, SiO2, and SiC all increase monotonically with the rf power. However, with increasing pressure the Si etch rate increases while the etch rates of ...