SURFACE REACTIVITY OF CF2 RADICALS MEASURED USING LASER-INDUCED FLUORESCENCE AND C2F6 PLASMA MOLECULAR-BEAMS

The surface reactivity of CF2 radicals during plasma processing of a 3 00 K Si substrate using the imaging of radicals interacting with surfa ces (IRIS) technique is reported. The molecular beam sources are 100% C2F6 and 50:50 C2F6/H-2 plasmas. Under IRIS conditions, there is no ne t film deposition in the former system, while the latter deposits a fl uorocarbon polymer film. Simulation of cross-sectional data shows a CF 2 surface reactivity of -0.44 +/- 0.03 with 100%C2F6 and of 0.16 +/- 0 .02 using 50:50 C2F6/H-2. A negative reactivity indicates CF2 molecule s are generated through plasma processing of the substrate. Possible C F2 surface generation mechanisms are discussed.