Stress Relaxation Study in 3C-SiC Microstructures by Micro-Raman Analysis and Finite Element Modeling

Abstract

In this paper, micro-Raman characterizations and Finite element modeling (FEM) of microstructures (cantilever, bridge, planar rotating probe) realized on single-crystal (100) 3C-SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm-1) respect to the stressed unreleased region (795.7 cm-1). The TO Raman mode exhibits an intense shift, up to 2 cm-1, located on the undercut region, where the Silicon substrate starts to be released. Such effect is ascribed to the modification of the Raman stress tensor that makes the generalized axial regime, described by diagonal components of the Raman stress tensor, unsuitable to describe the stress status on this region. Raman maps analysis and FEM simulations show the “activation” of the shear stress, i.e. non-diagonal components of the stress tensor. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer.