Residual stress in underlying silicon at the fixed end of SiO2 microcantilevers — A micro-Raman study

Abstract

In this work, nature of the residual stress developed in the convex corners created in underlying Si at the fixed end of SiO2 microantilevers (MCs) fabricated by wet chemical etching method was investigated using micro-Raman spectroscopy with visible excitation. It revealed the presence of tensile stress near the sharp edge of the convex corner and is attributed to the localized stress generated in the neighborhood of the discontinuities, acting as stress concentration region. Residual stress estimated by micro-Raman technique across the convex corner was also validated by FEM simulations. Micro-Raman also revealed the presence of tensile stress on the etched Si surface, which is explained on the basis of stress induced by native oxide shells covering the etched features.