Strain-induced Kirkendall mixing at semiconductor interfaces

We use molecular dynamics computer simulations to study the damage production by collision cascades at Si/Ge and AlAs/GaAs and InAs/GaAs interfaces. For the arsenide systems we find that present interatomic potentials have troubles in describing even the basic elastic and melting properties. We report parameter refinements which give a significantly better description of these properties. Our results for collision cascades at strained semiconductor interfaces show a strong asymmetry in the distribution of vacancies and impurities produced at the interface. The effect is explained as a strain-induced effect analogous to the classical Kirkendall effect. We also show that although the chemical composition of compound semiconductors does not strongly affect the overall evolution of collision cascades, the composition may in some cases have a significant effect on the final distribution of defects.