Enhanced growth mechanism in lateral solid-phase epitaxy of Si films simultaneously doped with P and Ge atoms

Lateral solid-phase epitaxy (LSPE) characteristics of Ge-and P-incorporated amorphous Si films deposited on SiO2/Si(100) structures have been investigated and a model for explaining the enhanced growth has been proposed. The growth rate is enhanced for the Ge concentration around 0.5 at.% and it is even further enhanced by simultaneous doping of Ge and P atoms. In order to investigate the origin of the enhanced growth, Ge atom profiles and stress distributions along the LSPE direction have been investigated using cross-sectional transmission electron microscopy (TEM), electron probe microanalysis (EPMA) and microprobe Raman spectrometry. A main cause of the enhanced growth was shown to be the residual stress in Ge-incorporated alms. From this a model to explain the stress effect due to incorporation of Ge atoms has been derived, in which the critical thickness theory for pseudomorphic growth of SiGe alloy layers is taken into consideration.