BONDING STRUCTURE IN PLASMA-POLYMERIZED FILMS OF VINYLTRIMETHYLSILAN

Plasma polymer films of vinyltrimethylsilane (VTMS) were deposited by radiofrequency (RF, 13.56 MHz) or Microwave (MW, 2.45 GHz) discharges in two reactors of the same volume and geometry. - The polymer films were characterized by electron spectroscopy for chemical analysis (ESCA) and infrared spectroscopy (FTIR). It turned out, that the RF - and the MW - polymers had almost the same Si/C-composition ratio of 1/5 in the entire range of RF- and MW-power (60-150 W). Although the Si/C film-composition remains almost constant, the binding states of Si- and C-atoms in the respective ESCA-spectra are changing. While the C - Si part of the C1s-peak increases with the RF- or MW-power, the C - H/C - C part of the peak decreases, indicating a loss of hydrogen in the polymer films. - Obviously the fragmentation of the VTMS-monomer is quite different for the two types of plasma discharges. While films of the RF-plasma clearly show strong contributions of the methyl and vinyl groups, these groups are completely missing for the MW-plasma polymers. - From these results structure models of the plasma polymers have been developed.