THICK POLYCRYSTALLINE SILICON FOR SURFACE-MICROMECHANICAL APPLICATIONS - DEPOSITION, STRUCTURING AND MECHANICAL CHARACTERIZATION

Polysilicon films are deposited in an epitaxial batch reactor. The dep osition rate is of the order of 0.5 mu m min(-1), which makes a layer thickness oi 10 mu m or more possible. These films are deposited on a sacrificial oxide with a thin LPCVD polysilicon nucleation layer on to p. A wafer stepper is used for the lithography, The dry etching of the polysilicon is performed by applying hard mask technology. The values fur the residual stress, stress gradient and fracture strength make t his material highly suitable for surface-micromachining applications.