Effect of remote oxygen-plasma for SiOx film preparation

Effects of the remote oxygen-plasma irradiation in the plasma polymerization of organic silicon compounds were investigated from the viewpoint of chemical composition. Tetramethylsilane (TMS), dimethyldimethoxysilane (DMDMOS), and tetramethoxysilane (TMOS) (used as organic silicon compounds)were activated by glow discharge at 20 kHz frequency and irradiated by the remote oxygen-plasma at 13.56 MHz frequency. The deposited plasma films with and without the remote oxygen-plasma irradiation contained carbon residues as well as siloxane structures. The remote oxygen-plasma irradiation made the carbon contents low in the deposited plasma films; C/Si atom ratios for deposited films prepared from TMS, DMDMOS, and TMOS were 0.38, 0.54, and 0.40. On the other hand, for deposited plasma films without the remote oxygen-plasma irradiation, C/Si atom ratios were 1.2, 1.2, and 0.64. The deposited plasma films with the remote oxygen-plasma irradiation from TMS, DMDMOS, and TMOS had a similar chemical composition each other and contained Si-(O)(4) groups as a result of almost complete oxidation of silicon. These results indicate that the remote oxygen-plasma irradiation is a good way to prepare SiOx films.