Infrared spectroscopy study of adsorption of silane on Si(0 0 1)

We used infrared absorption spectroscopy in the multiple internal reflection geometry to investigate the adsorption of SiH₄ on the Si(0 0 1)(2 × 1) surface. Comparing infrared data with the density functional cluster calculation, we show that at low hydrogen coverage the silane molecule dissociatively adsorbs on Si(0 0 1)(2 × 1) to populate a dihydride (SiH₂) at the bridge site between two adjacent dimers and monohydride species; monohydrides are formed by terminating the unsaturated dangling bonds of dimers by hydrogen atoms released from the silane molecule. We suggest that at high hydrogen coverage, silane adsorbs onto a single dimer to generate monohydride and sylil groups (-SiH₃). We also demonstrate that the dihydride species that is initially generated by silane adsorption, decomposes to monohydride species even at room temperature.