The influence of heavily-doped substrates on the homoepitaxial growth kinet
ics of Si on Si(111) is studied in real time by means of reflection high-en
ergy electron diffraction as function of temperature and growth rate. The g
rowth experiments were performed by means of molecular beam epitaxy, The ob
tained results were compared with the growth kinetics on undoped substrates
within the framework of nucleation theory. It was found that in comparison
with undoped Si(111), the nucleus density in the case of Si(111):P is sign
ificantly increased at the same growth conditions that can be attributed to
a longer lifetime of the smallest stable islands consisting of a Si pair o
n the Si(111):P surface. It can be concluded, therefore, that phosphorus is
always present on the growing surface during high-temperature preparation
of heavily P-doped Si(111). There, the phosphorus atoms saturate dangling b
onds at the island edges. For further island growth, phosphorus atoms have
to be displayed before silicon adatoms can be incorporated into the island
edges, demanding an additional energy. In this sense, phosphorus acts as a
surfactant. (C) 2000 Elsevier Science S.A. All rights reserved.