臺灣博碩士論文加值系統

本論文利用寬能隙之氧化鎵薄膜摻雜氧化鋁材料，以達到提高薄膜調變能隙寬度及扼制缺陷產生之效果，藉由800 ℃熱退火處理，改善氧化鎵之結晶特性，製作出有效抑制表面態位及懸鍵缺陷之氧化鎵薄膜，藉此降低元件暗電流及改善響應特性，透過氧化鋁材料之摻雜使氧化鎵檢測波段由 250 nm調至235 nm，形成具有藍移趨勢之金屬-半導體-金屬深紫外光檢測器。
本實驗以兩個部分做為研究，一為優化氧化鎵薄膜性質，由改變熱退火處理溫度，以使得氧化鎵薄膜轉為β相性質且有效抑制缺陷。薄膜採磁控式射頻共濺鍍系統進行製備並於熱退火處理800 ℃條件下達最佳元件特性，於偏壓5 V時暗電流為5.86×10-12 A、響應度為0.173 A/W及紫外光-可見光拒斥比(UV-visible rejection ratio)為1216。另一方面氧化鎵薄膜更藉由氧化鋁材料摻雜，利用不同氧化鋁摻雜功率來改變氧化鎵薄膜之能隙，於摻雜功率200 W時達到光學能隙由5.01 eV增加至5.38 eV 之偏移量，而在摻雜功率為175 W，具有較佳特性，其暗電流為1.31×10-12 A、響應度為0.081 A/W及紫外光-可見光拒斥比為1538，等效雜訊功率則由原先未摻雜氧化鋁之7.05×10-12 W降至2.80×10-12 W，而檢測度由5.43×1010 cmHz1/2W-1增加至1.37×1011 cmHz1/2W-1

In this study, in order to fabricate a thin film that possessed the effect of tuning bandgap widely and suppressing the generation of defects, we used Ga2O3 doped Al2O3 as material due to Ga2O3 is a wide bandgap material. By annealing at 800 0C, the results showed that surface sites and defects of dangling bond would be controlled efficiently. Consequently, this process can lower the dark current of device and improve response characteristics. By doping Al2O3 in Ga2O3 thin film, the cut-off wavelength of Ga2O3 thin film can change from 250 nm to 235 nm. Thus, the metal-semiconductor-metal ultraviolet photodetector that appeared the trends of blue-shift formed.
The experiments of this study can be divided into two parts. One is to enhance the properties of Ga2O3 thin film. By changing the annealing temperature, when Ga2O3 thin film turned into β-phase, this situation can suppress defects efficiently. When operating bias was 5 V, the optimum device conditions for dark current, response, and UV-visible rejection ratio were 5.86×10-12 A, 0.173A/W, and 1216 respectively. Another is that we can adjust the bandgap of Ga2O3 thin film by doping Al2O3 with different sputtering power. The results showed that the bandgap of Ga2O3 thin film would enhance from 5.01 eV to 5.38 eV under the condition of sputtering power was 200 W with doping Al2O3. With 175 W applied, the devices showed the best characteristics, dark current, resposivity, and UV-visible rejection ratio were 1.31×10-12 A, 0.081 A/W, and 1538, respectively. Compare with the devices without doping Al2O3, the NEP was decreased from 7.27×10-12 W to 2.76×10-12 W, the detectivity of without doping Al2O3 and with doping Al2O3 were 5.26×1010 cmHz1/2W-1 and 1.39×1011 cmHz1/2W-1, respectively.

摘要 I
Abstract III
SUMMARY V
致謝 X
目錄 XII
表目錄 XVI
圖目錄 XVII
第一章 序論 1
1.1 氧化鎵材料 1
1.2 紫外光檢測器 2
1.3 研究動機 3
參考文獻 5
第二章 原理簡介 11
2.1物理氣相沉積系統 11
2.1.1 物理氣相沉積 11
2.1.2 濺鍍原理 11
2.2 光檢測器之相關理論 12
2.2.1 光的吸收及放射 12
2.2.2 薄膜穿透及光學能隙之計算 13
2.3 金屬-半導體接面理論 13
2.3.1 歐姆接觸 14
2.3.2 蕭特基接觸 14
2.4 光檢測器工作原理 17
2.4.1 金屬-半導體-金屬光檢測器工作原理 18
2.4.2 電壓電流特性曲線 19
2.4.3 光檢測器之響應度、外部量子效益與內部增益 20
2.5 低頻雜訊 22
2.5.1 熱雜訊 22
2.5.2 產生-復合雜訊 23
2.5.3 閃爍雜訊 24
2.5.4 等效雜訊功率及檢測度 24
參考文獻 35
第三章 元件製程及量測儀器 38
3.1 製程機台 38
3.1.1 磁控式射頻共濺鍍系統 38
3.1.2 電子束蒸鍍系統 38
3.2 量測儀器 39
3.2.1 UV-VIS-NIR分光光譜儀 39
3.2.2 X光繞射分析儀(XRD)量測 40
3.2.3 能量分散式光譜儀(EDS)量測 40
3.2.4 響應度系統量測 41
3.2.5 低頻量測雜訊系統 41
3.3 元件製程 42
3.3.1 藍寶石基板清潔 42
3.3.2 黃光定義元件吸收層(光罩圖型a) 43
3.3.3 元件吸收層製程 43
3.3.4 高溫爐薄膜熱退火處理 44
3.3.5 黃光定義元件蕭特基接觸金屬指狀電極製程(光罩圖型b) 44
3.3.6 指狀金屬電極之製程 45
參考文獻 53
第四章 元件特性量測與分析 54
4.1 薄膜量測結果 54
4.1.1 薄膜X光繞射量測分析 54
4.1.2 能譜能量散射分析儀量測分析 54
4.1.3 薄膜穿透率量測分析 55
4.2 不同熱退火之光電元件特性量測 56
4.2.1 暗電流量測 56
4.2.2 響應度對光波長之關係特性 57
4.3 不同氧化鋁製程功率元件特性 58
4.3.1 暗電流量測 59
4.3.2 響應度對光波長之關係特性 59
4.4 低頻雜訊分析 60
參考文獻 75
第五章 結論 77

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Chapter 3

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Chapter 4

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