Organosilicon thin films deposited from cyclic and acyclic precursors using water as an oxidant

Pulsed-plasma chemical vapor deposition was used to deposit thin films from four different organosilicon precursors using water as the oxidant. The precursors varied in structure, chemical composition, and type of organic substituent. Differences in film structure were observed based on precursor structure and type of organic substituents. More reactive substituents, such as vinyl groups, facilitated cross-linking. At low power (200 W), film structure was dictated by precursor identity. At high power (400 W) film structure became more uniform and precursor identity was less important. Mechanical and thermal properties correlated with plasma power and could be explained by the continuous random network theory and percolation of rigidity arguments. Low-power samples are relatively soft, with hardness values between 0.13 and 0.54 GPa. High-power samples are more extensively crosslinked and oxidized, resulting in enhanced mechanical properties, and had hardness values between 0.68 and 3.2 GPa, depending upon precursor identity. Thermal stability was strongly correlated to the degree of cross-linking, with non-cross-linked films showing up to 30% thickness loss upon annealing. Cross-linked films exhibited less than 8% thickness loss. Dielectric constants for the films ranged between 2.4 and 4.3 and were primarily dependent upon the extent of oxidation and organic content remaining in the films. (C) 2004 The Electrochemical Society.