以微製程技術製備鋯鈦酸鉛壓電式微重量感測器

Microfabrication of PZT piezoelectric sensors for microgravimetric applications

廖昌昱(Chang Yu)

指導教授 ： 蔡章仁

國立中央大學/資訊電機學院/電機工程學系/碩士(2007年)

摘要

本論文使用溶膠凝膠法(sol-gel method)製備不同感測面積之鋯鈦酸鉛(PZT)薄膜，之後再利用旋轉塗佈法(spin-coating method)配合微製程技術製作出PZT壓電感測器。藉著X-Ray繞射實驗、電流密度、鐵電分析及阻抗量測，來分析壓電薄膜特性與品質。於本實驗微製程製備下，感測面積過大的試片，壓電薄膜常有較多的雜質與缺陷導致短路而失去本身特性，而以感測面積範圍從80 × 80 μm2到400 × 400 μm2於目前製程技術下特性較好也較易成功，且其共振頻率位於90 MHz~100 MHz之間。
另一部分為外部電路的建構，採用電晶體所組成之共振電路來驅動，並應用一般FM廣播接收IC，將類比共振頻率訊號轉換成直流電壓，最後使用Labview DAQ介面將系統連結至電腦，進而直接於電腦上觀察並監控感測訊號的變化。初步將水滴滴在感測晶片上可得到5~20 kHz的頻率變化，蛋白質(BSA)重量與頻率下降關係實驗方面，每95 ng之BSA所造成的頻率下降平均值為9.503206 kHz，標準差為0.538882 kHz，靈敏度為62.8 Hz cm2/ng
本實驗藉由微製程的技術使晶片微小化，提升晶片感測的靈敏度，並藉由周邊感測電路系統的整合製作，期望成為可攜式、高靈敏度及穩定的微重量感測系統，提供未來生物分子如蛋白質的重量感測。

關鍵字

鋯鈦酸鉛 ； 壓電感測器

並列摘要

Our research adopted microfabrication technology to create miniaturized piezoelectric sensors from PZT thin films with different sensing areas prepared with sol-gel method. The characterization and quality of these sensors were examined through X-Ray diffracting measurements, leakage current density analysis, ferroelectricity analysis and impedance measurements. From the results of those analyses, sensors with larger detecting areas failed more easily due to more impurities and defects. Better performances could be obtained with sensor areas from 80 × 80 μm2 to 400 × 400 μm2, with which the resonant frequencies were between 90‐100 MHz.
The other part of our research was the construction of peripheral circuits. We built transistor-based resonant circuits with PZT devices. The resonant frequency was detected with a conventional FM receiver IC, which transformed the frequency signal into a voltage output. The output was observed and monitored on the computer. Preliminary experiments showed that dripping the water on the sensing area caused a frequency change of 5‐20 kHz.
Our miniaturization and using of PZT material led to portable, sensitive and stable piezoelectric sensors. We expect the sensor system to be applicable in protein sensing in the future.

並列關鍵字

PZT ； piezoelectric sensor

參考文獻

[20] 饒珮瑩, “利用微機電技術設計及製作壓電式微型加速計”, 國立成功大學航太系碩士論文, 民國92年7月。

[1] P. L. Konash, and G. J. Bastiaans, “Piezoelectric Crystal as Detectors in Liquid Chromatography,” Anal. Chem., vol. 52, pp. 1929-1931, 1980.

[2] T. Nomura, “Single-Drop Method for Determination of Cyanide in Solution with a Piezoelectric Quartz Crystal,” Anal. Chim. Acta, vol. 124, pp. 81-84, 1981.

[3] T. Nomura, and M. Iijima, “Electrolytic Determination of Nanomolar Concentrations of Silver in Solution with a Piezoelectric Quartz Crystal,” Anal. Chim. Acta, vol. 131, pp. 97-102, 1981.

[4] M. Thompson, C. L. Arthur, and G. K. Dhaliwal, “Liquid-Phase Piezoelectric and Acoustic Transmission Studies of Interfacial Immunochemistry,” Anal. Chem., vol. 58, pp. 1206-1209, 1986.