Stability of Boron- and Gallium- Induced Surface Structures on Si(111) During Deposition and Epitaxial Growth of Silicon.

We have undertaken a new set of experiments to investigate the behavior of adsorbed-impurity induced reconstructions at growth interfaces. We have observed a striking difference in the stability of the B sqrt 3 x sqrt 3 and Ga sqrt 3 x sqrt 3 two-dimensional structures at the interface between Si(111) and a-Si, and in the segregation behavior of boron and gallium during molecular beam epitaxy crystal growth. This leads to a new model of dopant behavior in silicon molecular beam epitaxy.