Nanocrystalline silicon carbide thin films by fluidised/packed bed chemical vapor deposition using a halogen-free single source

Abstract

Thermal stability, vapor pressure, and binary gaseous diffusion coefficients of organosilanes were studied at temperatures in the range of 309–507 K in ambient pressure. The temperature dependence equilibrium vapor pressure (p_e)_T data yielded a straight line, when ln p_e was plotted against the reciprocal temperature, leading to a standard enthalpy of sublimation (Δ_sH°) values of 43.3 ± 0.6, 68.2 ± 0.8 and 72.4 ± 0.6 kJ mol⁻¹ for 1,4-bis(trimethylsilyl)butadiyne (TMSBu), 1,4-bis(trimethylsilyl)benzene (TMSB), and 1,4-bis[(trimethylsilyl)-ethynyl]benzene (TMSEB) and vaporisation (Δ_vH°) values of 33.9 ± 0.2 kJ mol⁻¹, 44.3 ± 0.6 kJ mol⁻¹, 64.5 ± 0.5 kJ mol⁻¹, 75.8 ± 0.6 kJ mol⁻¹, and 94.3 ± 0.4 kJ mol⁻¹ for triphenylsilane (TPS), 1,4-bis[(trimethylsilyl)-ethynyl]benzene (TMSEB), triphenylvinylsilane (TPVS), 1,1,2,2-tetraphenyldisilane (TPDS), and 1,2-dimethyl-1,1,2,2-tetraphenyldisilane (DMTPDS), respectively. In order to find the enthalpy of formation (Δ_fH°) at the condensed and gaseous state of each molecule at standard temperature, the semi-empirical quantum chemical analysis was carried out. The screened/selected ideal candidate was used to deposit silicon carbide thin films on the carbon black or silicon or zirconia particles in the fluidised/packed bed reactor. The deposits were characterized using X-ray diffraction and scanning electron microscopy methods.