An electrical probe for measuring thermal expansion coefficients of micromachined polysilicon thin films

In this paper, we present a novel electrical test structure for determining the thermal expansion coefficients (TECs) of micromachined polysilicon thin films. The electrothermal properties of the test structure are analyzed. The pull-in method is exploited in characterizing TECs of thin films. In addition, an analytical model and a measurement method are developed. The finite element software ANSYS is used to support the electrothermal analytical model. The test structure is fabricated using standard surface micromachining technology, and it is characterized under the natural operation environment. Measured average value of TEC is 2.48 × 10^-6 K^-1 from 300 K to 364.8K.