H₂-TPD study on the difference in the growth kinetics between SiH₄- and Si₂H₆-GSMBE

Hydrogen desorption kinetics from a Si(100) surface grown by gas-source molecular beam epitaxy (GSMBE) using either silane or disilane has been studied with temperature-programmed-desorption (TPD) measurements. For each source gas, a series of TPD spectra was obtained from surfaces quenched from the growth at various temperatures. The TPD spectra from disilane-GSMBE-grown surfaces showed no shift in the peak temperature, while those from the silane-grown surfaces showed a peak shift towards higher temperatures by 25°C at hydrogen coverages below 0.3 ML. This shift, indicative of the presence of higher-order desorption kinetics, suggests a more isolated configuration of the adsorbed hydrogen on the silane-grown surfaces. Difference in the growth kinetics between silane and disilane is also discussed.