臺灣博碩士論文加值系統

本次研究整合了多晶矽雙接面奈米帶元件之焦耳熱效應以及電漿原子層沉積技術，使我們的氣敏材料二氧化錫能在無光罩的情況下選擇性的修飾在我們元件之低摻雜區(n-)，利用高低摻雜( n+ /n- /n+ )結構之雙接面多晶矽奈米帶元件施加電壓時低摻雜區之焦耳自熱，結合電漿輔助原子層沉積(PE-ALD)系統之不同溫度時之沉積行為特性，選擇性沉積二氧化錫奈米結構於多晶矽奈米帶元件之低摻雜區，並應用於氫氣以及氨氣的感測。由於輕摻雜的緣故，n- 區域相較n+ 具有較長的迪拜長度，意味著他在感測上會較為靈敏，除此之外，我們也透過外部加熱的方式交叉比對出不同電壓下n- 區域之表面溫度，並且探討局部加熱對ALD成長速率的影響。在PE-ALD系統中合成之二氧化錫薄膜以二醋酸二丁基錫(DBTDA)做為前驅物，並透過ellipsometry、SEM以及XPS分析其材料特性，另外，藉由比較不同的基板溫度、電漿功率、反應循環數之等參數所沉積之材料特性，選擇出元件最佳之沉積參數。製備好的元件被裝設在以PDMS製成的小腔體進行氫氣以及氨氣的檢測，並透過施加不同的電壓自我加熱找出元件最適合之工作溫度，此外，我們也量測不同濃度之氫氣，以及不同環境下之氨氣感測特性，最後，我們提出了基於功函數之感測機制模型。

In this thesis, we utilized device-localized Joule heating in plasma enhanced atomic layer deposition (PE-ALD) system, for selectivity deposition of tin oxide(SnO2) nanostructure in the n- regions of n+ /n- /n+ polysilicon nanobelts (PNBs) as a gas sensor. Due to the lightly doping, The n- region has longer debye length than n+ region, it means that this region will more sensitive. Additionally, the n- region surface temperature was estimated via thermal chuck I-V(T) measurements for ALD deposition. SnO2 thin film synthesized by PE-ALD using dibutyltin-diacetate(DBTDA) as precursor, and the material characteristic was investigated by ellipsometry, SEM and XPS. Besides, the process parameters were optimized as functions of the substrate temperature, plasma power, the number of process cycles. Prepared device were settled in a small PDMS chamber to perform hydrogen and ammonia detection, and the working self-heating temperatures were investigated for the best response in both hydrogen and ammonia sensing. Furthermore, we also analyzed different concentration hydrogen in the range of 10 to 1000 ppm, and the ammonia sensing property under different carrier gas. Finally, model of work function-based sensing mechanism was presented.

中文摘要 II
ABSTRACT III
致謝 IV
目錄 V
圖目錄 VII
表目錄 X
第一章、 緒論 1
1-1 前言 1
1-2 氣體特性簡介 3
1-2-1 氫氣(Hydrogen, H2) 3
1-2-2 氨氣(Ammonia, NH3) 4
1-3 氧化物半導體(Semiconductor Metal Oxide, SMO)奈米結構氣體感測器 6
1-3-1 電阻式氣體感測器 6
1-3-2 功函數式氣體感測器 9
1-4 化學式閘極場效電晶體(Chemical Gated Field Effect Transistor, CGFET) 10
1-5 氧化錫(SnO2) 12
1-5-1 二氧化錫特性 12
1-5-2 氣體感測之應用 12
1-6 原子層沉積(Atomic Layer Deposition, ALD) 13
1-6-1 原子層沉積 13
1-6-2 電漿輔助原子層沉積技術合成二氧化錫 14
1-7 焦耳熱選擇性沉積之應用 15
1-8 研究動機與實驗架構 18
1-8-1 研究動機 18
1-8-2 實驗架構 18
第二章、 元件製備與材料製程 19
2-1 多晶矽奈米帶元件製作流程及特性 19
2-2 多晶矽奈米帶之溫度分析 24
2-3 電漿輔助原子層沉積技術合成二氧化錫 26
2-4 局部焦耳熱效應輔助選擇性沉積二氧化錫 28
2-5 氣體感測系統 29
第三章、 結果與討論 31
3-1 PE-ALD合成二氧化錫於矽基板上之薄膜分析 31
3-1-1 ALD Window 31
3-1-2 XPS(X-ray Photoelectron Spectroscopy) 分析 32
3-2 局部焦耳焦耳熱效應輔助選擇性沉積二氧化錫於矽奈米帶元件 38
3-3 感測機制 39
3-3-1 二氧化錫氣體感測機制 39
3-3-2 雙接面矽奈米帶元件之感測機制 42
3-3-3 溫度影響感測機制 45
3-4 氣體量測 46
3-4-1 氫氣感測 46
3-4-2 氨氣感測 52
第四章、 結論與展望 57
4-1 結論 57
4-2 未來展望 57
參考文獻 58

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