Adsorption and abstraction of atomic hydrogen on the Si(1 1 0) surfaces

The abstraction reaction of D adatoms by H atoms have been investigated on the Si(1 1 0) surfaces. The direct abstraction to form HD molecules obeys a second-order rate law in D coverage θD. On the other hand, the indirect abstraction to form D2 molecules obeys a fourth-order rate law in θD. In addition to the direct abstraction, indirect abstraction to form HD molecules is also included due to piled H adatoms during H exposure. It is found that the indirect abstraction is promoted on the surfaces saturated with dideuterides, suggesting that dideuterides (dihydrides) play a significant role in the indirect abstraction paths. The kinetics of the abstraction reactions on the Si(1 1 0) surfaces look similar to those on the Si(1 0 0) surface. However, the delayed D2 desorption exhibits time profiles different from those on the Si(1 0 0) surfaces.