H+ desorption and hydrogen pairing on the hydrogenated Si(100) surface

We report the desorption of H+ ions from hydrogenated Si(100) surface under the irradiation of 193 nm pulsed laser beam. The observed two groups of H+ ions with mean kinetic energies of 0.09+/-0.05 and 0.38+/-0.06 eV are assumed to correspond, respectively, to the H+ ions desorbing from doubly occupied and singly occupied dimers and the difference of 0.29+/-0.11 eV in their kinetic energies corresponds to the pairing energy on the H/Si(100) surface. The dependence of the H+ yield on the laser fluence follows approximately a cubic law and the H+ desorption cross-section is sigma approximate to 10(-73) cm(6) s(2). The experimental results are compared with the earlier studies of H+ desorption as well as the more recent report of neutral H desorption from the H/Si(100) surface. (C) 2000 Elsevier Science B.V. All rights reserved.