本論文探討利用超音波霧化熱裂解法沉積氧化鋁於氮化鋁鎵/氮化鎵高電子遷移率電晶體之研究。並探討將氮化矽與氧化鋁使用雙疊鈍化技術應用於氮化鋁鎵/氮化鎵高電子遷移率電晶體，以獲得較佳之可靠度及較低漏電流。
為瞭解超音波霧化熱裂解法所形成之氧化層的組成，在本論文中使用了原子力顯微鏡、穿透電子顯微鏡、化學分析電子儀與霍爾量測進行探討。在原子力顯微鏡量測中，可以驗證成長的薄膜相當的均勻。在穿透電子顯微鏡中，觀察成長的薄膜厚度為20奈米。在化學分析電子儀中的縱深分析，可得知氧化層中的化學成分組成確認是氧化鋁。在霍爾量測中，發現利用超音波霧化熱裂解法沉積氧化鋁使得片電子濃度有所上升而電子遷移率有些許下降。除此之外，我們也利用遲滯效應與表面狀態密度判定鈍化製程所能降低表面缺陷之幅度。
在瞭解薄膜之材料分析後，進一步研究氮化矽、氧化鋁以及雙疊鈍化技術應用於氮化鋁鎵/氮化鎵高電子遷移率電晶體上。我們發現使用雙疊技術在漏電流特性可抑制至3.6×10-4 mA/mm與氮化矽之漏電流為2.9×10-2 mA/mm，相較後有較佳的特性表現。此外，使用雙疊技術的元件與氧化鋁相比有更佳的抗腐蝕以及可靠度能力。
而超音波霧化熱裂解法沉積氧化鋁於金氧半高電子遷移率電晶體上，先利用比較不同厚度找出最佳的元件特性，同時也發現在厚度為20奈米的氧化層之元件有最佳的特性改善。在電流電壓特性可操作至4伏特閘極電壓，崩潰電壓可承受至182伏特。除此之外，在功率表現上，功率附加效率提升至42 %，因此超音波霧化熱裂解法沉積氧化鋁之元件具有提升高功率以及高頻率元件之潛力。

This research proposes the investigation of aluminum oxide (Al2O3) and stacked Si3N4/Al2O3 on the AlGaN/GaN high electron mobility transistors (HEMTs) by using ultrasonic spray pyrolysis deposition (USPD). We found that the stacked Si3N4/Al2O3 on the AlGaN/GaN HEMTs achieved better reliability and lower leakage current.
In order to analyze the oxide layer composition, we utilized the atomic force microscopy (AFM), transmission electron microscopy (TEM), electron spectroscopy for chemical analysis (ESCA), and Hall measurement in the research. We observe that the surface roughness is quite uniform by AFM. Then, we confirm that the thickness of oxide layer is 20 nm through TEM. Besides, in ESCA analysis, the results show the oxide layer is exactly Al2O3. Moreover, Hall measurement is compared with passivated device, the sheet concentration is increased and the electron mobility slightly reduced. In addition, the decreased oxide layer trap density is confirmed by the hysteresis and interface state density.
Si3N4, Al2O3, and stacked passivation are applied to the fabrication of AlGaN/GaN HEMTs. We found that stacked passivation device can suppress gate leakage to be 3.6×10-4 mA/mm which is better than 2.9×10-2 mA/mm of Si3N4-passivated device. Furthermore, anti-corrosion and reliability of the stacked passivation device is better than Al2O3-passivated device.
Finally, we propose that the Al2O3 oxide layer applied to metal-oxide-semiconductor (MOS) HEMTs by using ultrasonic spray pyrolysis technique is studied the optimal thickness of the oxide layer is 20 nm. The gate voltage of device can be operated up to 4 V and the breakdown voltage is -182 V. Moreover, the power-add efficiency (P.A.E.) achieves 42 %. Therefore, the device which passivated Al2O3 on the AlGaN/GaN HEMTs by using ultrasonic spray pyrolysis technique is suitable for high power and high frequency applications.

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