Plasma polymerization of hexamethyldisilane ([CH3]3SiSi[CH3](3)) and tetramethylsilane ([CH3]Si-4) has been investigated by XPS, FTIR, solid state NMR, and plasma emission diagnostics. Thin carbosilane films and powders can be deposited by this method. Hexamethyldisilane is found to undergo glow discharge polymerization much more readily than tetramethylsilane; this has been attributed to the chromophoric "Si-Si" bond contained in the former precursor.