LPCVD of silicon carbide films from the organosilanes diethylsilane and di-t-butylsilane

In this paper, the kinetics and properties of amorphous LPCVD silicon carbide films synthesized from the single organosilane precursors diethylsilane (DES) or di-t-butylsilane (DTBS) are discussed, For DES, the growth rate is observed to vary linearly with flow rate and pressure, pressure, while for DTBS, a square root dependency is seen as a function of these parameters. An Arrhenius type behavior was observed for both chemistries yielding activation energy values of 40 and 25 kcal/mol for DES and DTBS respectively. The elemental composition of the films became progressively richer in carbon as the deposition temperature increased with stoichiometry occurring near 750°C. The film stress was dependent on carbon content and became compressive at compositions near Si_0.35c_{0. 65}. The hardness and Young's modulus of the films increased with increasing carbon content reaching maxima near stoichiometry. Free-standing membranes produced under optimal processing conditions had a relatively low optical transmission due to excess carbon. Although, transmission characteristics were improved by adding NH₃ in the reaction chamber, the resulting silicon carbonitride films exhibited undesirable high values of tensile stress.