1997 American Vacuum Society National Symposium (San Jose)

TITLE:
Interaction of Se with Si(111): A Photoelectron Diffraction Study

AUTHORS:  Shuang Meng, Brett R. Schroeder, Michael A. Leskovar and
Marjorie A. Olmstead

ABSTRACT:

The structure and composition of a silicon surface after exposure
to individual constituent elements are crucial in understanding the
initial formation of compound heteroepitaxial films.  The initial stages
of film growth often involve saturation or reaction of substrate dangling
bonds.  For example, the growth of GaAs on Si(111) begins with As
saturation of the substrate dangling bonds, whereas the initial growth of
ZnSe/Si(100) involves Se reaction with surface Si, forming SiSe@sub
2@.  In this study we have looked at Se/Si(111) as the initial step in
GaSe or ZnSe growth on Si(111). We have used X-ray photoelectron
spectroscopy (XPS), component-resolved X-ray photoelectron diffraction
(CR-XPD) and low energy electron diffraction (LEED) to study the growth
of Se on clean Si (111) 7x7 at various substrate temperatures. Our LEED
observations indicate that the adsorption of Se on Si(111) surfaces does
not lead to an ordered termination of the 7x7 surface. We find that the
growth of Se reaches a saturation coverage during exposure of Si samples
at temperatures above 380 C and our XPS data  are consistent with a
monolayer or submonolayer coverage of Se. Deposition of Se at room
temperature followed by annealing at higher temperatures leads to
similar results. In either case our preliminary CR-XPD studies show no
interdiffusion of Se at the interface and no evidence of SiSe@sub 2@
formation.