The paper presents an improved bimorph cantilever beams fabrication process by simply using three masks. Due to the difference of thermal coefficients of expansion between layers, the free end of the beam bends as the temperature increases. For a typical fabricated bimorph cantilever beam with a length of 217 μm and a width of 132 μm, the vertical displacement reaches 93 μm at a DC current of 33.9 mA and a input power less than 60 mW. Another beam of 357 μm by 100 μm illustrates a displacement up to 156 μm at the power of 63 mW (20 mA). The testing results indicate that the current bimorph cantilever beam with a shorter length will induce bigger displacement than that of previous research. The results of finite element simulation indicate that a 2% maximum error exists under 7 V. A thermally driven microvibrator, which vibrates vertically, is fabricated. This microvibrator consists of four bimorph cantilever beams and a thin plate. The microvibrator can move up and down about 5 μm at the DC current of 30 to 60 mA. The amplitude is diminished apparently when the frequency of the AC current exceeds 60 Hz.
|Number of pages||7|
|Journal||Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao|
|State||Published - 1 Dec 1997|