title: Polycrystalline silicon micromachining: a new technology for integrated sensors.
abstract: Polycrystalline silicon (poly-Si) micromechanical structures can be made by selectively etching an underlying sacrificial oxide layer. Advantages of this micromachining technique are its simplicity and compatibility with conventional integrated-circuit processing. Compressive internal stress in poly-Si films constrains the dimensions of microstructures; fortunately, it can be reduced through annealing. Fabrication of an integrated vapor sensor incorporating a resonant poly-Si microbridge and on-chip NMOS circuitry is described. Frequency response measurements imply that poly-Si films have a Young's modulus of 4 X 10(10) Nm-2, substantially lower than crystalline silicon. A potential application of poly-Si micromachining is fabrication of an integrated pressure transducer; evaluation of this device identifies areas for further research.
mesh_terms: D001698:Biomedical Engineering / Q000295:instrumentation*; D003460:Crystallization; D004582:Electronics, Medical; D011108:Polymers; D012825:Silicon; D014160:Transducers, Pressure
chemical_list: D011108:Polymers; D012825:Silicon