Surface Accumulation of Boron During Si Molecular Beam Epitaxy

Abstract

ABSTRACTA high temperature, elemental boron evaporation source has been used for the study of the boron doping behaviour in Si as a function of growth temperature and doping level. Significant profile smearing of boron at doping levels below 5×1018cm−3 is observed. Profile smearing is more severe in higher doped samples for growth temperatures above 600°C at a growth rate of 0.28 nms−1. This is interpreted as arising from the formation of a surface phase of boron at higher doping levels. The marked improvement in profile abruptness at low temperatures suggests significant benefits associated with the use of an elemental boron source for the growth of high resolution Si/Si1−xGex device structures.