本論文是利用SOI-MEMS共振器陣列與放大電路的整合來實現熱致動壓阻感測之微機械振盪器，其最大特色在於不需使用奈米結構，因此可大幅提升製程良率，在配合放大電路後，僅需要原自振式元件所需直流電流的七分之一便可完成振盪器功能，並且具有1.6 V之峰對峰值振幅輸出，可提供時脈與感測之功能。我們在空氣中量測到共振器元件的頻率響應，並得到67 dB背景阻抗訊號之降低，以及Q值最大可達到4,300的優異表現。若作為質量感測器使用，我們利用頻率計數器量測其Allan Deviation並計算其頻率漂移特性，最低可得到23.8 pg的質量解析能力，並利用鎖相迴路架設進行Nano-printer與抽氣實驗量測，可以得到相當線性的頻率變化量，對應到商用光學式氣膠感測器的濃度校正結果亦有非常高的濃度變化關聯性。
熱致動壓阻感測的運作原理，主要為使用電源供應器給予一直流電源，使致動器端產生焦耳熱效應用以推動質量塊，並讓結構運動在共振頻上，使運動可以放大Q倍而得到位移最大值。在輸入適當的直流電流伴隨放大電路的迴授訊號可使元件輕易地滿足振盪條件，使結構開始振盪，再藉由壓阻效應產生輸出之電訊號。
在元件設計上，我們必須使用負的壓阻係數材料搭配良好的結構導電性，感測器選用單晶矽材料並朝向[100]方向來獲得最大壓阻係數；我們利用陣列結構的設計來實現全差動之操作，以消除背景電阻訊號的影響，使共振頻訊號不被掩蓋，並得到相當優異的Stopband rejection；在製程上僅運用兩片光罩與乾、濕蝕刻即可完成高製程良率的陣列結構，並且可以藉由二氧化矽當作Hard mask縮小致動器寬度來增進元件的性能，使直流的驅動功率可以降低至數mW等級。
本研究在量測的表現上，MEMS元件在空氣中最低的操作直流功耗為9.6 mW，並大幅降低元件的操作溫度，低電流操作下僅升溫3.5˚C，此為自振式元件的十一分之一；相位雜訊在1 kHz與100 kHz分別有-80.05 dBc/Hz和-100.18 dBc/Hz的表現，並由質量感測器的量測表現顯示，PM1煙霧濃度提升的可使共振頻變化由-4.74 Hz/s增加至-7.2 Hz/s，其微粒感測的完整量測結果皆會在本文中進行詳細的介紹。

This work implements an integrated system consisting of a MEMS resonator and an amplification circuitry to realize a variety of thermal-piezoresistive (TP) oscillators. By using various structures and dimensions of the thermally actuated beams, different resonance frequencies and device performances can be obtained. It is also notable to point out that the system level integration would potentially relax the fabrication constraints, such as nano-structures, and greatly lower down the DC biasing current level for an SOI TP oscillator as compared to that of the conventional self-sustained single II-BAR oscillators. The proposed devices demonstrate quality factor of around 4,300 in air and 67 dB feedthrough reduction via a fully-differential mode of operation. To serve as a mass sensor using the proposed TP oscillators, their Allan deviation measurement from the frequency counter indicates that the mass resolution of 23.8 pg is achievable. The measurement results of TP devices integrated with a lock-in and PLL circuitry present a high linearity of the frequency drift by nano-printer imprinting experiment. A real-time aerosol sensor utilizing an SOI-MEMS TP oscillator with calibration by a commercial optical aerosol sensor (OAS) has shown a high correlation between the frequency slope of the TP oscillator and the calibrated readings from the OAS.
This thesis describes the principle and operation of TP oscillators. The device characteristics are analyzed by finite element simulation and electronic design software. With combination of an adequate DC current source and a driving ac signal at its resonance frequency, the structure starts to oscillate through system integration with the loop gain greater than one and loop phase close to zero.
In order to achieve high motional conductance, we design the piezoresistors aligned with [100] lattice direction of an SOI device layer to obtain maximum value of the negative longitudinal piezoresistive coefficient. In order to reduce feedthrough level to attain a decent resonant response with high stopband rejection, array design together with miniaturization of the actuator beam width using special processes will also enable the device oscillation under a low power operation mode. This work presents the device characteristics of II-BAR arrayed resonators. It only requires 9.6 mW DC power to enable oscillation in air, with only 3.5˚C rise of temperature, and phase noise performance of -80.05 dBc/Hz at 1-kHz offset and -100.18 dBc/Hz at 100-kHz offset, respectively. Finally, the particulate matter (PM) sensing measurement under smoke (liquid-phase PM1, 1 μm diameter) has shown a frequency decreasing trend from 4.74 Hz/s to -7.2 Hz/s based on the increasing of particle concentration in the environment. The entire particle sensing measurement will be presented in detail in this thesis.

摘要...i
Abstract...iii
誌謝...v
目錄...viii
圖目錄...x
表目錄...xvi
第一章 前言...17
1-1 研究動機與背景...17
1-2 文獻回顧...20
第二章 原理分析與模擬...28
2-1 熱致動壓阻感測式振盪器運作原理...28
2-2 熱致動壓阻感測式振盪器設計與模擬...31
2-2-1 MEMS共振器...31
2-2-2 放大電路與系統整合...32
第三章 微製程與結果...42
3-1 SOI元件製程...42
3-2 元件製程結果...47
3-2-1 白光干涉儀檢視...47
3-2-2 SEM檢視...48
第四章 元件量測與分析...56
4-1 開迴路量測...56
4-1-1 De-embedded訊號處理...57
4-1-2 Fully-differential量測架設...58
4-1-3 系統整合量測...59
4-2 閉迴路量測...66
4-3 鎖相迴路量測...71
4-4 IR量測...79
4-5 質量感測器量測...82
4-5-1 Nano-printer量測...82
4-5-2 氣膠抽氣量測...89
4-5-2-1 Solid particles量測...96
4-5-2-2 Liquid droplets量測...103
第五章 結論與未來研究...106
參考文獻...110

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