Adsorption and decomposition of 1,4-disilabutane (SiH3CH2CH2SiH3) on Si(100) 2×1 and porous silicon surfaces

Abstract The adsorption and decomposition of 1,4-disilabutane (SiH 3 CH 2 CH 2 SiH 3 ) (DSB) was studied on Si(100) 2×1 and porous silicon surfaces. Temperature programmed desorption (TPD) studies revealed that H 2 and ethylene (C 2 H 4 ) were the major reaction products from Si(100) 2×1. These reaction products were also confirmed using laser induced thermal desorption (LITD) techniques. In addition, Auger analysis showed only ∼0.2–1.7% carbon deposition after saturation DSB exposures on Si(100) 2×1. This surprisingly low carbon incorporation may be explained by the efficient C 2 H 4 desorption pathway. Fourier transform infrared (FTIR) spectra obtained after DSB adsorption on porous silicon surfaces at 200 K showed the presence of mostly SiH 3 vibrational modes and the absence of CH 3 vibrational features. These spectral characteristics suggest initial dissociative chemisorption of DSB through Si–C bond breakage. The FTIR spectra versus thermal annealing were consistent with a progressive SiH 3 →SiH 2 →SiH decomposition and a di-σ “ethylene-like” intermediate that produces the C 2 H 4 desorption product. LITD studies also tested for the presence of SiH 3 surface species on Si(100) 2×1 following DSB exposures and observed SiH 3 LITD signals. Comparisons with LITD results following disilane saturation exposures suggest different bond breaking pathways for DSB and disilane adsorption on Si(100) 2×1.