Strain-induced Kirkendall mixing at semiconductor interfaces

We use molecular dynamics computer simulations to study the damage producti on by collision cascades at Si/Ge and AlAs/GaAs and InAs/GaAs interfaces. F or the arsenide systems we find that present interatomic potentials have tr oubles in describing even the basic elastic and melting properties. We repo rt parameter refinements which give a significantly better description of t hese properties. Our results for collision cascades at strained semiconduct or interfaces show a strong asymmetry in the distribution of vacancies and impurities produced at the interface. The effect is explained as a strain-i nduced effect analogous to the classical Kirkendall effect. We also show th at although the chemical composition of compound semiconductors does not st rongly affect the overall evolution of collision cascades, the composition may in some cases have a significant effect on the final distribution of de fects. (C) 2000 Elsevier Science B.V. All rights reserved.