Strain-driven self-positioning of micromachined structures

We introduce a method to make self-positioned micromachined structures by u sing the strain in a pair of lattice-mismatched epitaxial layers. This meth od allows the fabrication of simple and robust hinges for movable parts, an d it can be applied to any pair of lattice-mismatched epitaxial layers, in semiconductors or metals. As an application example, a standing mirror was fabricated. A multilayer structure including an AlGaAs/GaAs dielectric mirr or and an InGaAs strained layer was grown by molecular-beam epitaxy on a Ga As substrate. After releasing the multilayer structure from the substrate b y selective etching, it moved to its final position powered by the strain r elease in the InGaAs layer. (C) 2001 American Institute of Physics.