Infrared absorption spectroscopy in the multiple internal reflection geometry and hybrid density-functional cluster calculation are used to characterize the adsorption structure of hydride species that form during adsorption of disilane on Si(100)(2×1) at room temperature. We suggest that disilane dissociatively adsorbs without breaking its Si-Si bond to produce an adatom dimer, -H2Si-SiH2-, that bridges two adjacent dimers. We demonstrate that at low hydride coverage, a trihydride (-SiH3) formed by breaking the Si-Si bond of Si2H6, decomposes into dihydride and monohydrides, while at high hydride coverage, the trihydride decomposition is quenched. We also suggest that the impinging rate of adsorbing molecules has a significant effect on the adsorption kinetics.
Physical Review B
- Pub Date:
- February 2002
- Surface and interface chemistry;
- heterogeneous catalysis at surfaces;
- Chemisorption/physisorption: adsorbates on surfaces;
- Analytical methods involving electronic spectroscopy