We have studied the uptake process of H on Si (100) surfaces by means of rate-equation analysis. Flowers' quasiequilibrium model for adsorption and desorption of H [M. C. Flowers, N. B. H. Jonathan, A. Morris, and S. Wright, Surf. Sci. 396, 227 (1998)] is extended so that in addition to the H abstraction (ABS) and beta(2)-channel thermal desorption (TD) the proposed rate equation further includes the adsorption-induced desorption (AID) and beta(1)-TD. The validity of the model is tested by the experiments of ABS and AID rates in the reaction system H+D/Si (100). Consequently, we find it can well reproduce the experimental results, validating the proposed model. We find the AID rate curve as a function of surface temperature T, exhibits a clear anti-correlation with the bulk dangling bond density versus T, curve reported in the plasma-enhanced chemical vapor deposition (CVD) for amorphous Si films. The significance of the H chemistry in plasma-enhanced CVD is discussed. (c) 2005 American Vacuum Society.