SYNCHROTRON RADIATION STUDIES OF MBE FORMED SEMICONDUCTOR INTERFACES: Si-GaAs AND GaAs-Si

Abstract

Studies of silicon on gallium arsenide and gallium arsenide on silicon interface formation will be described and used as examples of how synchrotron radiation excited photoemission is a powerful probe of surface and interface phenomena. The samples and interfaces studied in this work were prepared in-situ using thermal Ga and As MBE sources and a resistive Si evaporation source. The MBE capability has allowed us to explore atomic and electronic structural issues of interface formation during hetero-epitaxy. We have combined these techniques to explore Si and GaAs surfaces, the adsorbate interactions of Ga and As on Si, and interface formation of Si on GaAs and the inverse system, GaAs on Si. Several of these surfaces and interfaces yield model systems which can provide general insights. As an example, studies of arsenic terminated silicon (100) and (111) surfaces will be described. A specific focus of the paper will be the interfacial development of Si on GaAs(100). Si deposited at various coverages below 10 ml onto a room temperature substrate yields a disordered surface. For coverages below two monolayers, subsequent annealing at 450–600°C leads to a single domain 1×2 surface from either the As rich c(2×8) or Ga rich 4×6 reconstructions. While the periodicity is the same for the different starting surfaces, evidence is presented that the atomic arrangement in the unit cell is different.