New structural model for Si/SiO2 interfaces derived from spherosiloxane clusters: implications for Si 2p photoemission spectroscopy

The differential reactivity of octahydridosilsesquioxane on Si(100)-2x1 and Si(111)-7x7: a comparative experimental study

Scanning tunneling microscopy (STM), in conjunction with X-ray photoemission (XPS) and reflection-absorption infrared (RAIRS) spectroscopy, has been used to investigate the reaction of octahydridosilsesquioxane clusters (H(8)Si(8)O(12)) on the Si(100)-2x1 and Si(111)-7x7 surfaces. The clusters exhibit a markedly different reactivity upon exposure to the two clean silicon surfaces. STM data is presented that, in conjunction with XPS and RAIRS data, provides numerous constraints upon possible geometries for the chemisorbed clusters. The sum of the data is consistent with a dissociative reaction mechanism on Si(100)-2x1, resulting in cluster attachment to the surface via a single vertex. Conversely, data of Si(111)-7x7 subject to a saturation exposure of H(8)Si(8)O(12) is presented that is highly suggestive of cluster decomposition on the surface.

Determination of spherosiloxane cluster bonding to Si(100)-2 x 1 by scanning tunneling microscopy

Scanning tunneling microscopy is used to determine the bonding geometry of the spherosiloxane cluster, H(8)Si(8)O(12) , on Si(100)-2 x 1. The images obtained are consistent with monovertex bonding to the Si(100)-2 x 1 surface via activation of a single Si-H bond. Filled and empty state images show good agreement with calculations of the electron density distribution of the cluster as well as the Psi(2) highest occupied molecular orbital and lowest unoccupied molecular orbital surface plots of the cluster.