RF frequency effects on molecular fragmentation

Abstract

The chlorine contents of 40 kHz and 13.56 MHz RF silicontetrachloride and dichlorosilane plasmas were investigated using actinometric evaluation in a parallel-plate (stainless-steel disk electrodes, stainless-steel reactor) electrode and in an electrodeless (external electrodes and glass reactor) discharges, in the 50-500 W RF power and 100-500 mTorr pressure ranges. It was found that the frequency has a significant effect on the molecular fragmentation of dichlorosilane and a less important effect on the fragmentation of silicontetrachloride. This behaviour was related to the molecular structures of the two starting components. The plasma-induced surface chemistries and morphology changes were also investigated and related to the different chemistries driven under 40 kHz and 13.56 MHz frequency environments. Plasma-induced and frequency-controlled molecular fragmentation reactions can be envisaged based on these findings.