STRUCTURES ON SI(100)2X1 AT THE INITIAL-STAGES OF HOMOEPITAXY BY SIH4DECOMPOSITION

The initial stages of homoepitaxial island formation on Si(100)2 x 1 b y SiH4 decomposition under ultra high vacuum chemical vapor deposition conditions are studied by scanning tunneling microscopy and kinetic m odel calculations. The concentrations of the intermediate species form ed on the surface during SiH4 decomposition are calculated from the ki netic parameters of the dissociation cascade leading to Si Blm growth in the temperature regime of 500 to 800 K and for SiH4 pressures in th e range of 2 x 10(-7) to 2 x 10(-5) mbar. Experimental results showing the surface topography after interaction with SiH4 at various surface temperatures and deposition rates are presented, and the observed sur face structures are related to the different surface conditions, i.e., deposition flux and sample temperature, under which islands are forme d.