We have studied the interaction of SiH4 with Si(100)2×1 and with Si(111)7×7 utilizing scanning tunneling microscopy. At 690 K Si deposition does not saturate, but the reactive sticking coefficient is considerably larger for Si(100)2×1. On this surface the 2×1 reconstruction is preserved during deposition. The anisotropy of the newly formed islands and the growth process are influenced by the presence of hydrogen from dissociated SiH4. In contrast, the Si(111)7×7 surface is completely restructured by the interaction with SiH4. This results in the formation of a bulklike hydrogen terminated 1×1 structure without any remnants of stacking faults. After exposure to 50 000 L SiH4 at 690 K not more than half a bilayer has grown, forming triangular Si(111)1×1-H islands.

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We have studied the kinetics of nucleation and growth during Si/Si(100)-(2ϫ1) homoepitaxy by ultrahigh vacuum chemical vapor deposition from SiH 4 , employing scanning tunneling microscopy and comparative rate equation simulations of the growth processes. Island formation in this highly complex system, in the presence of mobile hydrogen and other metastable SiH x species, is analyzed and compared to molecular-beam epitaxy growth and predictions from established rate equation theory. The deviations from classical theory can be understood by taking into account the kinetics of the SiH 4 dissociation cascade that leads to epitaxial Si growth.

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

The interaction between Si͑100͒2ϫ1 and SiH 4 under UHV chemical vapor deposition conditions between 550 and 690 K is studied with high-resolution scanning tunneling microscopy and kinetic model calculations.In addition to small anisotropic Si islands and patches of hydrogen-terminated substrate, metastable crossshaped structural tetramer units are formed in this temperature region. These tetramers are interpreted as a combination of four SiH 2 groups connecting four Si substrate atoms, and their coverage is correlated with the decomposition kinetics of SiH 2 . ͓S0163-1829͑97͒05707-X͔