Mechanical Properties of Polycrystalline 3C-SiC Films between Room Temperature and 600 °C

Abstract

Silicon carbide (SiC) is widely recognised as the leading candidate to replace silicon inMicro ElectroMechanicalSystems (MEMS) operating in harsh environments. In thiswork, cantilevers and bridges in polySiCare designed, fabricated and evaluated betweenroom temperature (RT) and 600 ºC. The structures are excited both mechanically andelectrostatically. Their resonance frequency is measured by Laser Doppler Velocimetryand used to derive the Young’s modulus and average residual stress in the heteroepitaxiallayer (330±45 GPa and 200±20 MPa, respectively). The temperature coefficient ofYoung’s modulus is found to be 53±2 ppm/K in the range RT to textasciitilde300 ºC, whilst ananalytical expression is given for the temperature dependency of the Young’s modulusbetween RT and 500 ºC.