Saturation adsorption reaction of cracked Si H on Si 001/and 2 6 Ge 001/

We have investigated the adsorption process of thermally cracked Si2H6 on a Si 001.and a Ge 001.surface using high-energy electron diffraction RHEED.and Auger electron spectroscopy AES.techniques. Upon exposure to thermally cracked Si2H6, their surface periodicities changed from 2=1 to 1=1, and the Si coverage determined using a Ge 001. surface is self-limited and its value is saturated at ;1 ML under the cracking temperatures from 200 to around 4008C. The rates of the Si 001.and Ge 001.surface periodicity changes as a function of thermally-cracked-Si2H6 dose are almost the same. The cracking conditions meet those of silylen :SiH2.formation. The AES and RHEED analyses also indicate that the 1=1 surface is strongly related to the structure of the surface saturated with a monolayer of Si adsorbates. The atomically flat 1=1 1 ML saturation adsorption process is expected to meet SirGe Atomic layer epitaxy ALE.growth conditions. q1998 Elsevier Science B.V. All rights reserved