A new miniaturized surface micromachined tunneling accelerometer

The authors have fabricated a new class of miniaturized surface micromachined tunneling accelerometers. The accelerometer structures are fabricated on the surface of a single silicon wafer and consist of a single cantilevered beam with electrostatic deflection electrodes and tunneling tip underneath. The noise level resolutions in air of 100-μm and 250-μm-long cantilever devices are 8.3×10/sup -4/ g/Hz¹2/ and 8.5×10/sup -5/ g/Hz¹2/ at 500 respectively. The devices are operated in a force rebalance feedback mode using a low noise automatic servocontrol circuit, providing a dynamic range of over 10⁴ g. This new accelerometer technology provides devices with extremely high sensitivity, high bandwidth and wide dynamic range, in an ultracompact, low-cost package that is easily integrated with silicon control electronics.