Electron beam effects on diethylsilane-covered Si(100) surfaces investigated by x-ray photoelectron spectroscopy

Ethylated silanes and germanes are promising candidates for heterojunction atomic layer epitaxy of SiGe devices. However, thermal dissociation of unwanted ligands in the parent molecules usually is not suitable for device fabrication. Hence, alternative means for dissociation employing low thermal budgets are desirable. In this work, an electron beam was used to irradiate diethylsilane (DES)-covered Si(100) surfaces at 100 K in order to initiate non-thermal, electron-driven dissociation and desorption processes in the adsorbed species. Clean Si(100) surfaces were dosed with gas-phase DES molecules at 100 K followed by irradiation with 600-eV electrons (current density 5.4 muA cm(-2)). The effects of electron irradiation were investigated by obtaining x-ray photoelectron spectra before and after exposing the DES/Si(100) to the electron beam. Shifts in the binding energy of the C Is photoelectron peak and a decrease in the total surface carbon concentration are indicative of dehydrogenation and removal of carbon species by electron irradiation. Our results suggest the possibility of electron-beam-assisted beta-hydride elimination at 100 K as one channel for surface carbon removal. Copyright (C) 2003 John Wiley Sons, Ltd.