Diethylsilane Decomposition on Silicon Surfaces Studied Using Transmission FTIRSpectroscopy

摘要

Fourier transform infrared (FTIR) transmission spectroscopy was used to monitorthe decomposition of diethylsilane (DES) (CH3CH2)2SiH2 on high-surface-area porous silicon samples. The FTIR spectra revealed that DES dissocitively adsorbs on porous silicon to form SiH and SiCH2CH3 species. The infrared absorbances of the CH2CH3 stretches at (2955 to 2879)/cm and the SiH stretch at 2088/cm were employed to monitor the decomposition of the SiCh2CH3 surface species. As the silicon surface was annealed to 500-750 K, the SiCH2CH3 species decomposed to produce gas phase ethylene CH2=CH2 and additional SiH surface species. These reaction products were consistent with a -hydride elimination reaction. Above 700 K, the SiH surface species decreased concurrently with the desorption of H2 from the porous silicon surface. In additional experiments, isothermal FTIR studies were performed the characterize the decomposition kinetics of SiCH2CH3 by -hydride elimination. The uptake of surface species was also monitored at various adsorption temperatures to determine the optimal DES exposure temperatures for carbon-free silicon deposition.