Cantilever Beam Micromachined Piezoresistive Acceleration Sensor

Micromachachined piezoresistive accelerometers based on the MEMStechnology are very important accelerometers The piezoresistive sensor require lowcost and simple signal processing circuitry, and are compeible with lC processing Asrcsult, the cost can be lowered while the sensitivity and the resolution can beimproved The lowest range of sensors is ±2g～500g, nonlinearity 0. 2%～l%,transverse sensitivity fatio l%～3% The low range piezoresistive accelerometersare widely used in movement controlling system and inlnenometor The automobileindustry meets the large need of the accelerometers in recent yearsIn this paper an introduction of the MEMS technology MEMS devices and itsapplication, inner stress analysis in interface between film and wafef, andmicromachined piezoresistive accelerometers were comprehenslvely surveyed inchapter l And the prospect of the MEMS technology and the micromachinedcapacitive accelerometers were studiedIn Chapter 2, the mechanism, static and dynamic characters, thermal charactersof the piezoresistive accelerometer with cantilever beam were studied in detail Aftertheoretical calculation, it can be conclusion that because the center of mass isn't incentral plane, inertial force will product bending stress in piezoresistance, is the mainsource of transverse sensitivityIn chapter 3, the process of sensors is elaborated, about the sensing element andcover board For correcting the displacement of mass because of inner stress inintetface SiO₂/S1₃, Si₃N₄. film was adoptedThe mechanism and discipllnanan of lnner stress was stUdled 1n chaPtr 4 It wasproved that the inner stress of multi-layers film is the summation of every single-layers film, and the displacement of the mass is proportional linearity to thickness ofevery single filmIn chapter 5, the static and dynamic characters of this sensors was measured andthe factor which affect sensors character was analyzed based on the measurement dataAs result, the piezoresistive accelerometer with cantilever beam with tange±1g,nonlinearity less than 0.05%, sensitivity～1mV/gV damping factor～o.7 and workbandwidth 110Hz show utility value...