本論文主要針對在低阻值矽（111）基板上進行氮化鋁鎵/氮化鎵電晶體製作與研究，並且使用原子層沉積（Atomic Layer Deposition, ALD）之複合氧化鋁（Al2O3）/氧化鉿（HfO2）/來實現常開型金氧半場效電晶體之特性。 電晶體製作採用氨氣（NH3）與三甲基鋁（trimethylaluminium, TMA）做表面處理和薄膜氧化層之熱退火（post-deposition annealing），進而改善了元件的漏電流。在汲極到源極距離為26 μm，閘極長度為2 μm的元件上實現出金氧半場效電晶體，其臨限電壓為-9.1 V，其汲極飽和電流為IDSS = 650 mA/mm，導通電阻2.6 mΩ‧cm2，元件的導通電流與截止電流比值為2 × 108 及次臨限斜率為88 mV/dec。三端元件的崩潰電壓約為800 V，其評比效能（Figure-of-Merit）為246 MV/cm2。 此外，針對蕭特基閘極場效電晶體與金氧半場效電晶體的動態導通電阻的進行量測分析，結果發現金氧半場效電晶體可獲得較低的動態電阻/穩態導通電阻比值，並討論溫度變化對動態電阻的影響。 This study focuses on AlGaN/GaN HEMTs on low-resistance Si（111）substrate with bilayer gate oxide（Al2O3/HfO2）by atomic-layer-deposition（ALD）to achieve the normally-on metal-oxide-semiconductor high electron mobility transistors. To fabricate metal-oxide-semiconductor high-electron-mobility-transistors, high-k Al2O3/HfO2（1/6 nm）gate dielectrics deposited by ALD were used with NH3 and TMA pre-treatments in this study. The NH3 pre-treatment was carried out before loading into ALD chamber, and TMA（50 cycles）pre-treatment was performed before Al2O3/HfO2 deposition in the ALD chamber. After Al2O3/HfO2 deposition, devices with and without post-deposition annealing（in N2 ambient at 450 C）were investigated and compared. Device（LG = 2 μm 、LGS = 4 μm、LGD = 20 μm）fabricated with NH3 and TMA pre-treatments and post-deposition annealing showed threshold voltage VTH of -9.1 V, drain saturation current Idss of 650 mA/mm, specific on-resistance Ron of 2.6 mΩ‧cm2, on/off current ratio of 2 × 108, sub-threshold slope (SS) of 88 mV/dec, beeakdown voltage of about 800 V, and the Figure-of-Merit of 246 MV/cm2. In addition, dynamic resistances of the Schottky-gate high electron mobility transistors and Metal-oxide-semiconductor high electron mobility transistors were analyzed. The experimental results showed that Metal-oxide-semiconductor high electron mobility transistors demonstrated lower dynamic resistance to steady-state resistance ratio. Moreover, the temperature variation of the dynamic resistance was discussed.
