Micromachining of thin 3C-SiC films for mechanical properties investigation

Abstract

AbstractIn this work, the mechanical properties of cubic silicon carbide are explored through the analysis of the static and dynamic behavior of 3C-SiC cantilevers. The investigated structures were micro-machined using Inductively Coupled Plasma (ICP) etching of thin 3C-SiC films grown on silicon. The aim was to evaluate the influence of some basic parameters (film orientation, film thickness, defect density) on the mechanical properties of the material.X-Ray Diffraction was used to evaluate the crystalline quality of the epilayers. Scanning Electron Microscopy observations of static cantilever deflection highlight the major difference between the stress states of (100) and (111) oriented layers for which the intrinsic stresses are of opposite signs. The cantilever deflection is highly dependent on the film thickness, as stated for (100) oriented epilayers. The lowest deflection is obtained for the thickest layer. The Young's modulus of 3C-SiC is calculated from the resonance frequency of clamped-free cantilevers, measured by laser Doppler vibrometry. The relatively low and orientation independent value of Young's modulus (~350GPa) found on the samples is probably associated with the high defect density usually observed in very thin 3C-SiC films grown on Si.