Critical width for coherent stripes

Abstract

Epitaxial stripes have found important applications in microelectronics. On growth beyond a critical thickness, interfacial misfit dislocations partially relax the misfit strains in hetero-epitaxial systems. In epitaxial stripes, the critical thickness at which a misfit edge dislocation becomes energetically favourable is expected to depend on the width of the stripe. In the current investigation, the variation in critical thickness is studied as function of the width of the stripe, by simulating an epitaxial system and a misfit edge dislocation, using finite element method. It is seen that for stripes below a certain critical width the coherent state is stable for all thicknesses of the stripe.