由於元件逐漸縮小限寬，電容值無法往增加面積及厚度縮減下提升，而為了解決這個問題，目前主要的趨勢採用高介電值材料做為閘極氧化層，可以有效的提升閘極的絕緣度，並有效降低元件的閘極漏電流，而二氧化鋯除了有高介電值之外，與其他的高介電值材料相比也有較高的能隙，而較高的能隙也可以抑制閘極漏電流的產生，因此我們研究以液向沉積法來成長二氧化鋯薄膜並應用於氮化鎵材料上，製作氮化鋁鎵/氮化鎵金氧半高電子遷移率電晶體。
液相沉積法是一種相當簡單的方法，並且有相當低的成本，以及可以在室溫下進行，避免高溫所產生的缺陷。並且經由X光譜儀可以確定二氧化鋯已沉積在氮化鎵材料上，並且利用原子力顯微鏡來觀察薄膜的表面狀態，以及掃描電子顯微鏡去確定薄膜的厚度。
在元件應用上，我們成功利用液相沉積法沉積二氧化鋯薄膜在氮化鋁鎵/氮化鎵高電子遷移率電晶體上，形成金氧半高電子遷移率電晶體，與傳統高電子遷移率電晶體比較，將可以提升最高的汲極電流密度，從496 mA/mm 提升到627 mA/mm，最大轉導由118 mS/mm降到92 mS/mm，在漏電流方面可以改善了超過10000倍，在順向崩潰電壓以及關閉狀態下的崩潰電壓，也將有顯著的改善。

Because of reducing dimensions of devices, the capacitance can’t increase by increasing the area and reducing the oxide thickness. Nowadays the dominating method is that using the high-k dielectric material to be gate oxidized layer which can improve gate insulation quality and reduce gate leakage current significantly. ZrO2 not only is high-k material but also has greater bandgap compared with other high-k materials which can also suppress gate leakage. In this thesis, ZrO2 film is prepared through liquid phase deposition and used as gate dielectric in AlGaN/GaN MOS-HEMT.
The liquid phase deposition method has advantages of easy operation, low cost, and deposition under room-temperature avoiding the defects producing by high temperature. By using XPS to demonstrate that ZrO2 film could be deposited on GaN. AFM is also used to observe the surface of the ZrO2 film and using SEM to confirm the film thickness.
The AlGaN/GaN MOS-HEMT with a liquid phase deposited ZrO2 as gate insulator is fabricated. Compared with the conventional HEMT, the maximum drain current density increases from 496 to 627mA/mm, whereas the peak extrinsic transconductance decreased slightly from 118 mS/mm to 92 mS/mm in the MOS-HEMT structure. The gate leakage current density of MOSHEMT improved significantly over 10000 times than conventional HEMT. The forward breakdown voltage and off-state breakdown improved with the oxide layer becoming thicker.

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