Kinetics of Ge Segregation in the Presence of Sb During Molecular Beam Epitaxy

Abstract

Kinetics of Ge segregation during molecular beam epitaxial growth is described. It is shown that the Ge segregation is self-limited in Si epitaxial overlayers due to a high concentration effect when the Ge concentration exceeds 0.01 monolayer (ML). As a result, segregation profiles of Ge are found to decay non-exponentially in the growth direction. This unusual Ge segregation was found to be suppressed with an adlayer of strong segregant, Sb, during the kinetic MBE growth. We develop a novel scheme to realize sharp Si/Ge interfaces with strong segregante. Lower limit of the effective amount of Sb for this was found to be 0.75 ML.