Microcrystalline silicon thin films for sensor applications

Abstract Resistivity and the piezoresistive effect have been investigated in doped microcrystalline silicon thin films, together with their temperature dependences. The layers were deposited in the crystalline state at 300 °C by a plasma-activated deposition process, and doped during deposition. The longitudinal piezoresistive effects in both n- and p-type layers are smaller than in single crystalline silicon, but show similar dopant dependences. The transverse piezoresistive effects in the layers are nearly independent of doping, which is different from the behaviour of a single crystal. An application of such thin films as strain gauges on a metallic membrane is described.