Role of hydrogen prepairing in the hydrogen desorption kinetics from Si(100)-2 x 1: effects of hydrogenating-gas and thermal history

Hydrogen desorption kinetics from Si(100)-2x1:H has been systematically inv estigated using temperature-programmed desorption (TPD) on several hydrogen ating gases and thermal conditions. As a result, the desorption kinetic ord er with the hydrogen coverage was found to increase in the order: atomic hy drogen <disilane <silane and room-temperature adsorption <high-temperature adsorption <post-annealing. These variations in kinetic order, depicted as a TPD peak shift at low hydrogen coverages, are universally described with a single surface parameter, gamma (o), the fractional coverage of unpaired hydrogen atoms. Fitting with obtained TPD spectra demonstrates that gamma ( o) is a delicate function of the hydrogenating gas and thermal history. (C) 2000 Elsevier Science B.V. All rights reserved.