Adsorption and decomposition of 1,4-disilabutane (SiH3CH2CH2SiH3) on Si(100)2x1 and porous silicon surfaces

The adsorption and decomposition of 1,4-disilabutane (SiH3CH2CH2SiH3) (DSB) was studied on Si(100)2x1 and porous silicon surfaces. Temperature program med desorption (TPD) studies revealed that H-2 and ethylene (C2H4) were the major reaction products from Si(100) 2x1. These reaction products were als o confirmed using laser induced thermal desorption (LITD) techniques. In ad dition, Auger analysis showed only similar to 0.2-1.7% carbon deposition af ter saturation DSB exposures on Si(100) 2x1. This surprisingly low carbon i ncorporation may be explained by the efficient C2H4 desorption pathway. Fou rier transform infrared (FTIR) spectra obtained after DSB adsorption on por ous silicon surfaces at 200 K showed the presence of mostly SiH3 vibrationa l modes and the absence of CH3 vibrational features. These spectral charact eristics suggest initial dissociative chemisorption of DSB through Si-C bon d breakage. The FTIR spectra versus thermal annealing were consistent with a progressive SiH3-->SiH2-->SiH decomposition and a di-sigma "ethylene-like " intermediate that produces the C2H4 desorption product. LITD studies also tested for the presence of SiH3 surface species on Si(100) 2x1 following D SB exposures and observed SiH3 LITD signals. Comparisons with LITD results following disilane saturation exposures suggest different bond breaking pat hways for DSB and disilane adsorption on Si(100) 2 x 1. (C) 1998 Elsevier S cience B.V. All rights reserved.