Kinetics of D abstraction with H atoms from the monodeuteride phase on Si(100) surfaces

The abstraction kinetics of D from the monodeuteride phase on Si(100) surfaces by H atoms was studied at 640 K as a function of the D coverage using direct product detection. HD and D2 were observed as products, with D2 accounting for 5.7% of the abstracted D. The HD kinetics does not follow an Eley–Rideal reaction scheme. At the completed monodeuteride layer, the abstraction probability per incoming H atom is 0.15, corresponding to an abstraction cross-section of σ=3 Å2. The kinetic features of HD and D2 can be explained through a hot-atom reaction scenario. Expressing adsorption and abstraction through Kisliuk-type kinetics, it is shown that the above value of the abstraction probability and the initial D sticking probability of 0.5 lead to a saturation coverage of close to unity. The existence of a recently observed strongly bound state of H was confirmed. D adsorbed on these sites are abstracted with smaller cross-section than from monodeuteride sites.