近年來，氮化鎵(GaN)以被廣泛研究，跟矽比起來有優良的材料特性。此外，在氮化鎵鋁(AlGaN)與氮化鎵的異質接面處發現了高密度的電子，研究其原因是由於自發性極化效應(Spontaneous Polarization)與壓電極化效應(Piezoelectric Polarization)所致，這些高濃度的電子被稱為二維電子氣，擁有相當高的電子遷移率，這些特性使得氮化鎵和氮化鎵鋁材料有很低的導通阻抗，非常適合高功率元件的應用。不過，還是有些問題，例如：normally-on、punch-through。
此論文的目的就是透過元件結構的改變以及相關參數模擬分析來實踐獲得高性能的高電子遷移率電晶體。我們提出一具有p-type埋入層之高電子遷移率電晶體，該模擬結果與傳統HEMT相比，其可獲得好的崩潰特性。

In recent year, gallium nitride (GaN), which is more excellent material properties than silicon and has been extensively studied. In addition, high electron density was found at the hetero-junction of aluminum gallium nitride (AlGaN) and gallium nitride. The main reason for this phenomenon is the spontaneous polarization effect and the piezoelectric polarization effect. These high electron concentration are called two-dimensional electrons gas. These features make gallium nitride and aluminum gallium nitride materials to have a low on-resistance. The HEMT is very suitable for high power device applications. However, there are some problems, such as normally-on and punch- through.
In this thesis, the HEMT device with a p-type buried layer is proposed. The resulting device characteristics are analyzed via process and device simulation. As compared to the conventional HEMT, this enhanced-mode HEMT device with p-type GaN buried layer can show much better breakdown characteristics.

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