以單晶片微機電諧振結構完成環境壓力感測器併讀出電路之設計

Abstract

本論文提出可於標準1P6M 0.18µm電路製程下，以單晶片微機電諧振結構完成之環境壓力感測器併讀出電路設計。藉由感測器之品質因子與環境壓力影響的關係，利用讀出電路來感測品質因子來偵測環境壓力。 在諧振器設計上採用梳狀式結構並以靜電力致動產生共振現象，藉由諧振器與品質因子之變化及感測電容變化轉換可得到輸出電流變化，利用轉阻放大電路讀取電流，最後透過峰值偵測器將諧振訊號波形轉成電壓準位。 根據量測結果，當壓力從100 Pa改變至1600 Pa時，諧振器之品質因子亦會從2566改變至452，其共振頻為15.4 kHz，並根據感測器設計讀出電路。在1.8 V的電源供應下，系統功耗為332.82 µW，靈敏度為0.0203 mV/Q。

A monolithic MEMS resonator based pressure sensor fabricated on the 0.18µm 1-poly-6-metal standard CMOS-MEMS process and monolithically integrated with TIA(trans-impedance amplifier) readout circuitry has been developed. Dependence of the quality factor and ambient pressures are well known to resonator designers and it will be feasible to integrate a readout circuitry of quality factor to detect ambient pressure. An electrostatic-actuated resonator generate current by capacitance changing with different quality factors. The TIA circuit converts current signal by resonator, then the output signal is converted from resonating waveform into voltage level by the envelope detector for ambient pressure estimation. By measuring the sample resonator, the air pressure changes from 100 Pa to 1600 Pa, the Q factor will change from 2566 to 452 with resonant frequency 15.4 kHz and the readout circuit is designed accordingly. The system power consumption is 332.82 µW with 1.8 V power supply and sensitivity is 0.0203 mV/Q.