Polymerized organosilicon films containing fluorine were fabricated using microwave plasma-enhanced chemical vapor deposition (MW PECVD). Chemical and physical surface properties were controlled by changing PECVD reaction conditions. Water-repellent films having water contact angles exceeding 150 degrees were obtained at Ts
=70°C and total pressure exceeding 40Pa.
Films were prepared from a mixed source gas of tetramethylsilane (TMS) or hexamethyldisilane (HMDS), containing no oxygen atoms, and a (heptadecafluoro-1, 1, 2, 2, tetrahydro-decyl)-1-trimethoxysilane (FAS-17). FAS-17 was introduced into a reactor using Ar carrier gas. Water contact angles of these films increased from 115 to 160 degrees as total pressure increased from 25 to 50Pa. Their surface roughnesses increased from Rrms
=11.3 to 60.8nm. The film structure became more granular when prepared at a higher pressure. With an increase in the substrate temperature, however, film surfaces became smooth and perfluoro-alkyl groups peeled from films, markedly decreasing in water-contact angles.
Films were then prepared from hexamethyldisiloxane (HMDSO), which contains oxygen atoms, and FAS-17 with Ar. Rrms
ranged from 10 to 12nm and contact angles remained constant at 110 degrees in the total 25∼50Pa. Oxygen atoms in the source material, i. e., HMDSO, promoted film surface smoothing and reduced water repellency.