Stabilization of temperature characteristics of micromirror for low-voltage driving using thin film torsion bar of tensile poly-Si

The micromirror with the tense thin film torsion bar can realize the low-voltage driving. The temperature characteristic is improved using polycrystalline (poly-) Si thin film taking advantage of the following features. The large tensile stress is obtained by the crystallization of amorphous (a-) Si film. The doping realizes the electrical connection. The poly-Si has the almost same coefficient of thermal expansion (CTE) with that of Si substrate.