Variations in Young's modulus and intrinsic stress of LPCVD-polysilicon due to high-temperature annealing

摘要: The effect of high-temperature annealing on Young's modulus E and the intrinsic stress sigma thin films made LPCVD-polysilicon was investigated. were annealed for 2 hours in a nitrogen atmosphere at temperatures between 600 degrees C 1100 C. Then determined by membrane deflection method. An extended analytical theory developed results correspond well with FEM analysis Pan J.Y. et al. (1990 Technical Digest, IEEE Solid-State Sensor Actuator Workshop, Hilton Head Island, SC, USA p 70). produced SiH4 flow rate 70 sccm total pressure 100 mTorr 620 film thickness 460 nm. For as deposited method yields 151+or-6 GPa an -350+or-12 MPa. After higher than deposition temperature compressive started to decrease increasing temperature. It relaxed nearly completely after seems increase little up 162+or-8 values obtained compared ultrasonic surface waves. waves systematically E. discrepancy can be explained uncertainty Poisson's ratio polysilicon.