HYDROGEN DESORPTION BEHAVIORS OF HF-TREATED SILICON-WAFER

Hydrogen desorption behaviors of HF-treated silicon wafer and decomposition reaction of water vapor on an HF-treated silicon surface under UHV were investigated by means of thermal desorption spectroscopy (TDS). When an HF-treated silicon surface was annealed in high vacuum, silicon trihydride species (SiH3) desorbed from the HF-treated silicon surface at 580-degrees-C, and SiH2F species which had probably the same structure as SiH3 on an HF-treated silicon surface desorbed and then recombined to form volatile SiH3-F with adjacent hydrogen at 580-degrees-C in addition to H2 desorption at about 400, 500 and 600-degrees-C. The decomposition reaction of water vapor was found to proceed in two steps at 500 and 750-degrees-C on a dehydrogenated silicon surface. The reaction made background hydrogen increase at 500 and 750-degrees-C in H2+ spectra from HF-treated silicon wafer.