| Summary: | 碩士 === 國立高雄大學 === 電機工程學系碩士班 === 97 === This thesis proposed a MOSFETs piezoresistive sensing method to discuss the current changed under the 0.135/0.45/10μm <110> channel lengths that are parallel (longitudinal) and perpendicular (transverse) to carrier channels by external stress. The devices are of 90nm technology silicon on insulator (SOI) MOSFETs. The studies found that the saturation current was reduced with increasing compressive stress except the PMOSFET on the longitudinal configuration, resulted from mobility change. The short channel devices were unobvious on piezoresistive effect due to significant parasitic resistance. Additionally, ring oscillators on wafer as tested bench were used as piezoresistive sensors to discuss the correlation of the abovementioned MOSFET by reading their oscillation frequencies. Ring oscillator were also designed to discuss the influence on piezoresistive effect. The thicker buried oxide of SOI MOSFET, result in higher oscillation frequency changed due to higher vertical electric field and scattering rate. The drifting resonance frequency of ring oscillators as piezoresistive sensor coincided with the results of piezoresistive MOSFET.
The second part of this thesis designed a square-shaped MEMS resonator for filter. The extensional and torsional vibration mode resonators and filters used CIC 0.35 CMOS MEMS process. The design, simulation and layout are demonstrated. The simulated resonant frequency of Lame mode, extensional mode and Lame-mode filter are 5.14~6.39, 7.98~9.51 and 5.14~6.39MHz, respectively.
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