Hybrid organic-inorganic xerogel films were deposited as porous thin films by spinning the precursor sol on silicon substrates. Films of various compositions were prepared using combinations of the following precursors: methyltrimethoxysilane, dimethoxydimethylsilane and tetramethoxysilane (TMOS). The hybrid films exhibited excellent gap-filling capabilities (0.45 micron trenches). Thermal desorption experiments indicate that heating to ∼130 C removes moisture and volatile organic constituents present in the as-cast film. Curing was found to increase the adhesion between the xerogel and the silicon substrate. Moisture was found to be responsible for an increase in the dielectric constant. That is, in ambient, the dielectric constant for a cured film was found to be 4.4; but in a dry atmosphere, it decreased to 2.5. Current-voltage measurements show the cured hybrid film possesses a breakdown field of 3.4 MV/cm.