CHARACTERIZATION OF ELASTIC STRAINS IN SEMICONDUCTOR HETEROEPITAXIAL LAYERS BY HREM

A new technique is presented to directly measure strains at the nanome ter scale from HREM images of heteroepitaxial semiconductor systems. T his approach involves the analysis of the cumulative sums of deviation s in lattice-fringe spacing from a target value. A brief discussion of the technique is given and applications to a simulated bilayer system as well as to an experimental image of a semiconductor superlattice a re presented. The CUSUM technique accurately reproduced the strain pro files in the systems investigated.