Time-of-flight distributions of HD molecules abstracted at a Si(1Â 0Â 0) surface

We study the dynamics of D abstraction by ∼0.05 eV H atoms on a Si(1 0 0) surface. Time-of-flight (TOF) distributions of the abstracted HD molecules are measured using a quasi-random chopper/cross-correlation method. The measured TOF distribution is found to be broad and fast. The distribution is decomposed into two components being related to direct abstraction (ABS) and adsorption-induced-desorption (AID), which were revealed in the kinetics studies. The best curve fits yield mean kinetic energies of 1.15 ± 0.20 eV and 0.33 ± 0.05 eV for the ABS and AID components, respectively. Dynamics and kinetics of hydrogen abstraction at Si(1 0 0) surfaces are consistently understood.