- 學位論文
應用可變增益電路之氫氣偵測器之研究
Investigation of a variable-gain circuit for hydrogen detector
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
本文提出由MEMS技術，結合標準CMOS技術製作之3乘3陣列式氣體感測器，藉由陣列式的多重輸入，能同時偵測不同製程之氫氣感測器。本感測晶片在製程上有兩大優點：1.元件陣列結構為懸橋式，當加熱器加熱時，懸橋結構能有效隔絕熱效應所造成之影響。2.採用Poly 2為微加熱器及感測電極材料，在製程上有良好相容性。元件結合可變增益放大電路，透過電路將元件感測之信號放大，以利量測及分析。以往的氫氣感測電路，大都將感測器及處理電路分開製作，此種做法往往造成訊號在介面處失真。本研究以晶片設計搭配微機電技術，透過佈局將感測器及信號前置放大電路整合一起，可減少晶片面積與達到整合效果，整個晶片分微感測器與感測電路兩部分，感測器部分，材料選用與氫氣有較大反應之觸媒金屬Pd；感測電路部分，因不同濃度之氫氣會有不同感測值，因此本電路設計了可變增益放大功能，在以往的放大電路中，常使用電阻比例做為放大信號的比例，此方法易受製程偏移影響，因此在本電路中將使用電容比例做為信號放大的倍率，透過這種作法將有效的改善DC offset所造成的輸出準位偏移影響以及配合交換式運算技術，搭配不重疊時脈信號對放大電路改善取樣時所產生的功率消耗，透過本電路之實現可有效整合感測電路、降低成本以及功率消耗。
並列摘要
In this thesis, a 3×3 gas sensors array with on chip multiple input integrated circuitry by using microelectromechanical system (MEMS) was fabricated. Hydrogen sensors fabricated with different structures can be measured simultaneously. The hydrogen sensing chip has two advantages. First, the structure of the array has a cantilever beam, it can prevent the hot effect. Second the fabrication can consistent with CMOS technology. It’s easy to measure and analysis by using the chip with variable-gain.Traditionally, the hydrogen sensing device and the sensing chip were divided. It will restrict the application due to the noise at the interface between the device and chip. Our device integrate the hydrogen sensing device and sensing circuit on the same chip. Palladium (Pd) is selected as the catalytic metal. Further more in contrast to the conventional amplifier, using resistance-ratio, our design amplifier base on capacitance-ratio can prevent the influence of fabrication parameters. The DC offset also can be improved. Finally, the designed circuit has the advantages of low cost and low power consumption.
參考文獻
[9] B. J. Huang, “Solid-state Electrolyte Based Electrochemical-gas Sensors”, Chemistry (The Chinese Chem. Soc., Taipei), 2001, Vol. 59, No. 2, pp. 207-217.
[2] C. Y. Huang, “The mechanism and application studies of hydrogenation reaction for metal catalyst on zero-valent metal”, Master Thesis, Department of Environmental Engineering and Management Chaoyang University of Technology, 2004
[5] M. H. Tseng, “Catalytic combustion type gas sensor”, Material and social, 1992, No. 68, pp. 57-61.
[6] Y. C. Chen, “Metal-oxide semiconductor-type gas sensors”, Material and social, 1992, No. 68, pp. 62.
[7] A. Mandelis and C. Christofides, “Physics, chemistry and technology of solid state gas sensor devices”, New York: John Wily & Sons, 1993.