Experimental and theoretical study of Young modulus in micromachined polysilicon films

The elastic modulus is a very important mechanical property in micromachined structures. Several design issues such as resonant frequencies and stiffness in the micromachined structures are related to the elastic modulus. In addition, the accuracy of results from finite element models is highly dependent upon the elastic modulus. In this study, the Young modulus of micromachined thin polysilicon films has been investigated with a new tensile test machine using a magnetic-solenoid force actuator with linear response, low hysteresis, no friction and direct electrical control. The tensile test results show that the measured average value of Young modulus for a typical sample, (164 ± 1. 2) GPa, falls within the theoretical bounds of the texture model. These results will provide more reliable design of polysilicon microelectromechanical systems (MEMS).