EBSD measurement of strains in GaAs due to oxidation of buried AlGaAs layers

We have characterized elastic strain fields associated with the wet-thermal oxidation of buried AlxGa1-xAs (x similar to 0.98) layers of thickness 80 nm, situated between GaAs layers of thickness 200 nm, on a GaAs substrate. The compressive strains accompanying oxidation can exceed 6% and may lead to interlayer delamination or fracture. Automated electron backscatter diffraction measurements were performed about individual oxide growth fronts on longitudinally cross-sectioned samples. We found that the elastic strain fields can be detected and mapped with a spatial resolution of better than 30 nm, using pattern sharpness quantification. Measured strain fields are elongated along the interfaces and extend approximately 1 mum around the growth front. We present efforts to quantify the spatial extent of these strain fields, as well as finite element simulations of the mechanics of oxide formation in this structure. (C) 2004 Elsevier B.V. All rights reserved.