Qm. Yu et P. Clancy, MOLECULAR-DYNAMICS SIMULATION OF CRYSTAL-GROWTH IN SI1-XGEX SI(100) HETEROSTRUCTURES/, Journal of crystal growth, 149(1-2), 1995, pp. 45-58
Pulsed laser-induced liquid phase epitaxy of SiGe alloy/pure Si substr
ate heterostructures, exposing both (100) and (111) orientations, has
been studied by nonequilibrium molecular dynamics (NEMD) simulation te
chniques using Stillinger-Weber potential models for the two component
s. Solid-liquid interfacial morphology, the quality of the regrown mat
erials and Ge redistribution at the interface were studied under both
fast and slow recrystallization conditions, controlled by the substrat
e temperature. For the (100) orientation, a significantly non-planar s
olid-liquid interface was found for all Ge concentrations, with Ge ato
ms at the bottom of this interfacial ''well'', causing solidification
to be retarded in their vicinity. For the (111) orientation, in-plane
defects with alternating structures of two five-membered rings and one
eight-membered ring were found in the regrown material due to the uns
table growth kinetics on the ''back'' side of the interface response f
unction. At slow crystallization rates, only stacking defects were fou
nd in the regrown material, without in-plane defects. The Ge partition
coefficient obtained from simulation at slow regrowth speeds is in go
od agreement with experimental measurements and also agrees well with
the prediction of Aziz's continuous growth model if the Ge diffusivity
at the solid-liquid interface and the width of the interface are used
in the calculation of the ''diffusive velocity''.