與CMOS製程相容之奈米碳管微機電氣體感測器

MEMS Gas Sensors Using Carbon Nanotubes With Full CMOS Compatibility

鄒秉寰(Ping-Huan Chou)

指導教授 ： 呂志誠

國立臺北科技大學/機電學院/製造科技研究所/碩士(2007年)

摘要

本研究提出一種可與CMOS與MEMS製程相容，使用多壁奈米碳管(MWCNTs)作為氣敏材料(gas-sensitive material)的氣體感測器。此感測器利用CMOS-MEMS製程，以微加工(micromachining)的方式製作具有介電薄膜及微加熱器的微熱板式化阻(chemoresistive)元件。而氣敏材料是在室溫下利用介電泳動(dielectrophoresis, DEP)方法排列沉積的，在DEP 過程中，MWCNTs因為受到電場極化的作用下聚結並沿著電場方向排列，最終成功地吸附在兩電極間。本研究完成了感測器結構的製作，及驗證了MWCNTs的感測特性，氣體測試結果成功地證實了奈米碳管對氮氣物理吸附(physisorption)的可逆性(reversible)，以及在2500~7500 ppm的氧氣濃度與120~300 ppm的一氧化碳濃度中，奈米碳管對感測氣體的響應，且敏感度隨著氣體濃度的升高而增加，藉由本研究的成果，對於結合多壁奈米碳管的氣體感測應用及實現CMOS智慧型氣體感測技術，提供了基礎而有效的整合經驗。

關鍵字

奈米碳管(CNTs) ； 微機電氣體感測器 ； 介電泳動(DEP) ； CMOS製程相容性 ； 薄膜結構

並列摘要

A class of multi-walled carbon nanotube (MWNT) gas sensors in consideration of CMOS and MEMS compatibility were proposed and developed. The sensor fabricated by CMOS-MEMS micromachining process was implemented on silicon substrate featuring a dielectric membrane and micro-heaters, and operated as a chemoresistive device. MWNTs were employed as active sensing clusters and deposited onto the membrane. MWNTs aligned laterally and linked with adjacent ones across electrodes through a room-temperature dielectrophoresis (DEP) process. Experiments to specify the sensor structure and verify sensing characteristics of MWNTs were carried out, and successfully demonstrate the reversible physisorption in response to the presence of nitrogen(H2) and sensing behaviour in response to the presence of oxygen (O2) between 2500 ppm and 7500 ppm, and carbon monoxide (CO2) between 120 ppm and 300 ppm. The more the gas concentration, the more the sensitivity. Based on this research results, it should be a fundamental and effective integration experience to combine MWCNT gas sensing applications with realization of CMOS smart gas sensor technologies in the near future.

並列關鍵字

carbon nanotube (CNT ； MEMS gas sensors ； dielectrophoresis (DEP) ； CMOS compatibility ； membranes structure

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