Ion dechanneling due to lattice strains in semiconductor superlattices

Abstract

A new source has been considered for the unusual ion dechanneling found in InAs-GaSb superlattices. This new source stems from the strains that occur in the layers because of the slight mismatch between the lattice constants of the two materials. The strains cause the rows and planes of atoms in the crystal that are inclined to the surface normal to have small directional misalignments at the interfaces between the layers. The effects of these misalignments have been incorporated into computer simulations of ion trajectories in the crystal and have been shown by means of the simulations to account in a reasonable manner for the observed dechanneling behavior. Two ways of measuring the amount of misalignment are suggested as a result of the simulations. Calculations have also been done as a function of the amount of misalignment to give some indication of how much dechanneling might be expected for superlattices composed of other pairs of materials with different degrees of mismatch.