The performance evaluation of CF/sub 4/ decomposition efficiency using 2- and 4-MHz power supplies was carried out as a function of the power, the pressure, the flow rate, and the quantity of O/sub 2/ addition. When the 2- and 4-MHz power supplies were used, almost complete CF/sub 4/ removal was achieved at 2.0 and 3.0 kW, respectively, when the CF/sub 4/ flow rate was 0.20 normal liters per minute. The optimum O/sub 2//CF/sub 4/ ratio should be in the range of 1.0/spl sim/1.25 in order to decompose CF/sub 4/ efficiently. The CF/sub 4/ decomposition efficiency using the 2-MHz power supply was significantly higher than that of the 4-MHz power supply under the same power, pressure, and flow rate. Significant amounts of byproducts such as COF/sub 2/ and CO were identified by the Fourier transform infrared spectrophotometer analysis in addition to CO/sub 2/.