本論文探討整體奈米柱狀結構的蕭特基PIN二極體式一氧化碳感測器的研製。首先在正型矽(100)基板上經由硝酸銀及氫氟酸蝕刻出矽奈米柱狀結構，再利用快速升溫化學氣相沉積系統(RTCVD) 藉由SiH4, H2, C3H8混合氣體於其上成長本質單晶碳化矽薄膜，然後在濺鍍各種不同負型的金屬氧化層(WO3、SnO2、ZnO等)，最後蒸鍍金屬鈀及鋁於最上面及背面分別作為催化層及金屬接觸層完成整個Pd/n-MOx/i-SiC/p-Si/Al PIN Schottky二極體的製作。
吾人利用FTIR、Raman、XRD 及SEM分別量測碳化矽薄膜原子間的鍵結，薄膜結晶及觀察表面結構和厚度來探討材料基本特性。此外，又分別選擇WO3、SnO2和ZnO三種不同金屬氧化物材料做為氣體感測層。由實驗結果發現，在三種不同金屬氧化物中以WO3對一氧化碳氣體的感測能力最佳。該元件在300℃，逆偏壓5V及100ppm的CO環境下，靈敏度達到463%。比沒有奈米柱狀結構感測器靈敏度9.31%相比和已發表者Au/WO3/SiN/p-Si結構於260℃，濃度3500ppm下的108%為佳。
本文也研究不同WO3厚度，碳化矽成長時間及操作溫度對於元件感測特性的影響。發現操作溫度在300℃時，WO3厚度為50nm、碳化矽薄膜為厚度100nm元件的感測特性最佳。一般而言，元件的感測能力隨著操作溫度升高而增加，但高到400℃時，元件整流特性遭到破壞，導致漏電流急速增加，使靈敏度降低。
最後，吾人也探討元件對感測氣體的選擇比，反應時間及再現性。發現對CO2及酒精氣體沒有明顯感測。在溫度300℃，濃度100ppm環境下有快速的反應時間(6秒)，元件的再現性也佳。

In this thesis, we developed the all nanorod structure Pd/MOx/SiC/Si PIN Schottky diode for CO gas sensing applications. Firstly, the Si nanorods were formed on the P type (100) Si substrate in AgNO3-HF mixed etching solution. Then the intrinsic β-SiC film was deposited on the top of Si nanorods with RTCVD(Rapid-Thermal Chemical Vapor Deposition)from the SiH4, H2, and C3H8 mixture gas. After that, various metal oxides such as WO3、SnO2 and ZnO were deposited as sensing elements. Finally, to complete the device structure by was deposited on the top of metal oxide layers as the catalyst and electrode contact, and Al on the bottom as the back contact.
The SiC thin films were analyzed by using FTIR, Raman, XRD and SEM for measurement of bond structure, analyzing crystallinity, and examination of surface morphology as well as film thickness, respectively. Experimental results showed the Pd/WO3/SiC/p-Si sample has the highest sensitivity of 463% under 300℃, 5v reverse bias and 100ppm carbon monoxide ambient. The sensitivity is higher than 9.31% and 108% for the counterpart without nanorod structures and that of the reported Au/WO3/SiN/p-Si structure, respectively.
Furthermore, effects thickness of WO3 and SiC films on the CO sensing ability were investigated. It was found that the device with a 50nm WO3 and 100nm SiC film has the highest sensitivity. Moreover, a higher sensing ability was increasing with a higher operating the CO temperature, while it began to degrade above 400℃ due to the rapid increasing leakage current of the device.
Finally, we investigated the selectivity and time response of the developed sensor. No significant CO2 and alcohol gas sensing actions were found. Besides, the sensor has a reproducible response time of ~ 6 sec under a 300℃and 100ppm CO ambient.

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