Investigation of strain distribution in LOCOS structures by dynamical simulation of LACBED patterns

Large-angle convergent beam electron diffraction (LACBED) dynamical simulations have been applied to the investigation of the strain distribution in the silicon region underlying a local oxidation of silicon (LOCOS) structure. This distribution is revealed through the modification of the profile of the (0 0 8) Bragg contour in the [1 2 0] projection of a [1 1 0] TEM cross-sectioned structure. If one assumes a strain field independent on the direction normal to the cross section, a contrast in the LACBED pattern is obtained only if a rotation of the lattice planes in the silicon region under stress is taken into account. The experimental patterns, taken on a submicron recessed-LOGOS, are in fair agreement with those calculated assuming, for the strain field, an analytical model based on the planar stress approximation (C) 1999 Published by Elsevier Science B.V. All rights reserved.