FINITE-ELEMENT ANALYSIS OF STRESS-RELAXATION IN THIN FOIL PLAN-VIEW TRANSMISSION ELECTRON-MICROSCOPY SPECIMENS

Finite element analysis has been used to model stress relaxation in thin foil plan-view transmission electron microscope specimens of strained epitaxial layers. Relaxation of the orders of 2%-20%, relative to the unthinned specimen, are determined for lattice strains of the order 1%, epitaxial layer thicknesses in the hundreds of angstrom regime and sample thicknesses of the order 1 mum. These calculations show that under carefully controlled experimental conditions, the stresses in thinned samples used for in situ electron microscope observations of dislocation dynamics in strained epitaxial layers are not substantially different from those in unthinned structures.