A Study on the Elastic Property Change with Temperature in Si Materials for MEMS

MEMS용 Si 소재의 온도에 따른 탄성 특성 변화에 관한 연구

  • Jung, Sung-Hoon (School of Materials Science and Engineering, Seoul National University) ;
  • Lee, Se-Ho (School of Materials Science and Engineering, Seoul National University) ;
  • Lee, Sung-Hun (School of Materials Science and Engineering, Seoul National University) ;
  • Kwon, Dong-Il (School of Materials Science and Engineering, Seoul National University)
  • Published : 2001.11.03

Abstract

Electrostatically actuated test devices were designed to evaluate the elastic modulus of single crystalline Si (100) materials for MEMS device. Elastic modolus was calculated from resonant frequency by applying Rayleigh's energy method. Temperature effect on elastic properties was evaluated by detecting the resonant frequency change with increasing temperature to $600^{\circ}C$. The elastic modulus was decreased with heating and then increased with cooling, but specimen with thermal cycle showed a permanent change which is lower than the initial value. This phenomenon was explained by the change of interatomic force and the formation of $SiO_2$ layer on Si. The thickness of oxide layer was estimated by considering the change of mass and stiffness, and the formation of oxide layer was observed by the SEM photograph.

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