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.