本研究主要為發展一種整合於CMOS製程的奈米碳管(carbon nanotube, CNT)濕度感測器之製造方法,其製作方式是將奈米碳管作酸洗處理,再以3-aminopropyltriethoxysilane (APTS)修飾矽晶圓上之SiO2層,使其表面形成具有氨根aminoterminated (–NH2)的自我組裝單分子層(self-assembled monolayer, SAM),而經處理過的表面存在正電荷與氨基群能與CNTs產生化學的吸附作用,使CNTs固定於元件表面形成感測薄膜,接著利用微影製程與濺鍍的方式將梳狀電極沉積於其上,以完成CNTs濕度感測元件的製作。 本研究之結果除了將此CNTs濕度感測元件之製程成功的應用於一般晶圓上以達量產之目的外,亦將此結果成功的整合於CMOS製程電路上達成晶片系統化(System on Chip, SoC)之目標,且由實驗發現,經酸洗處理之奈米碳管靈敏度高於未處理之奈米碳管,是因為經酸洗處理之奈米碳管測壁與末端有親水性羧基(-COOH)官能基群會提高對水的吸附。
The study demonstrates the fabrication of CMOS compatible humidity sensor based on CNTs. To begin with, CNTs were treated acid procedure, and then the SiO2 on the silicon wafer was modified by APTS in order to form an aminoterminated (–NH2) self-assembled monolayer (SAM), which could facilitate the chemical bonding between CNTs and amino-groups. By means of it, CNTs were immobilized on SiO2 to be the thin film of humidity sensing. Photolithography and Sputtering were then implemented to develop micro parallel electrodes. At last, it was completed the fabrication. In this study, we not only successfully develop a process to mass product CNTs based sensor, but also integrate it with CMOS circuits to achieve System on Chip (SoC). Moreover, from the experiment, the sensitivity of acid treated CNTs is surperior than untreated CNTs, which indicates the acid treatment can greatly enhance the adsorbability of CNTs to water by introducing hydrophilic carboxylic (-COOH) functional groups to the sidewalls and ends of CNTs.