本研究之目標乃是利用AlGaN/GaN 異質結構製作高崩潰電壓與高順向電流之蕭特基二極體，為了改善傳統蕭特基二極體具有大約1 V 開啟電壓（Von）以及過大之漏電流問題，本論文提出一個新穎的整流二極體結構，即P 型氮化鎵-場效蕭特基二極體（P-FESBD），此乃結合雙閘極金屬之蕭特基二極體與pn 接面二極體的設計概念，結構之特點乃是在閘極區域嵌入歐姆金屬，以降低元件的開啟電壓，而p-n 空乏區的作用則是在不需要recessed製程的情況下便達到常關型（normally-off）的操作特性同時降低反向漏電流，此外，由於P 型氮化鎵閘極的表面為歐姆接觸，因此當元件操作於順向偏壓時，P 型氮化鎵閘極會提供電洞注入通道降低開啟後電阻（Ron），完成後之元件獲得0.5 V 的低開啟電壓，開啟後電阻與崩潰電壓（VB）則分別為24 mΩ-cm2 與22 V，經由SIMS 與緩衝層電流量測的分析後發現鎂 （Mg）的擴散以及緩衝層材料的阻值皆是影響P-FESBD 元件特性的關鍵因素。另一方面為了改善傳統大面積蕭特基二極體因材料缺陷導致良率偏低的問題，本研究利用打線（wire bonding）並聯的方式製作陣列式蕭特基二極體，1.5 V 時可得順向電流432 mA，同時崩潰電壓仍維持在160 V。

In this thesis a new AlGaN/GaN high electron mobility transistor basedrectifier, i.e. P-field effect Schottky barrier diode (P-FESBD), is proposed andfabricated. It consists of a p-n diode and a Schottky diode connected in parallel.With the additional p-type GaN gate, the rectifier is expected to operate in the normally-off mode with low reverse leakage current and low on-resistance. The
turn-on voltage, on-state resistance and breakdown voltage of the one finger rectifier with 500×35 μm2 gate area is 0.5 V, 24 mΩ-cm2 and 22 V, respectively. According to secondary ion mass spectroscopy measurement and electrical
characterization, diffusion of the p-type dopant, Mg, and leakage current of the GaN buffer layer are concluded to be the main reasons for poor breakdown voltage.
Furthermore, in order to increase the forward current and yield of GaN Schottky diodes with multi-finger or large gate area, tested Schottky diodes are connected in parallel by wire bonding. Forward current of 432 mA at 1.5 V is achieved on a six-diode device with 160 V breakdown voltage.

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