本篇論文中，我們選用矽基板上磊晶p型氮化鎵/氮化鋁鎵/氮化鎵試片製作增強型高電子遷移率電晶體，主要於閘極區域利用高濃度的p型氮化鎵與底層氮化鋁鎵/氮化鎵形成PN接面的特性，空乏二維電子氣通道使通道關閉，藉此實現增強型元件。當元件通道長度2µm，閘極至源極長度5µm，閘極至汲極長度7µm時，量得臨界電壓值(Vth)為0.3V，轉移電導值為45mS/mm，導通阻抗值為3.43mΩ‧cm^2，以及不錯的電流開關比(Ion/off ≈10^8)。
在元件關閉崩潰特性方面，利用磊晶較厚的緩衝層(4.2µm)， 減少基板漏電路徑，同時提升垂直方向承受電壓能力。在基板為浮動電位並且浸泡在冷卻液的條件下，量測結果顯示，閘極至汲極長度為60µm元件，獲得最高崩潰電壓值為2760V。而閘極至汲極長度為20µm元件，則有最佳評比效能BFOM值604MW/cm^2，表示崩潰電壓與導通電阻達到最佳的平衡。最後，我們觀察到汲極電流呈現不穩定的現象，有別於表面與內部缺陷所導致的電流衰減，故嘗試分析並加以解釋可能成因。

In this thesis, enhancement-mode p-GaN/AlGaN/GaN HEMTs on a silicon substrate were fabricated. The p-type doped GaN and AlGaN/GaN barrier junction can be considered as a PN junction, so using p-type GaN as gate is able to deplete the 2DEG channel at a Vg=0V, thus yielding a normally-off device.
For the on-state characteristics, the threshold voltage (Vth) and the maximum transconductance (Gm,max) for the device with 2μm Lch, 5μm Lgs and 7μm Lgd is 0.3V and 45mS/mm. And the on-resistance and on/off current ratio is 3.43mΩ‧cm^2 and 10^8 for the same device.
For the reverse breakdown characteristics, we use a thick buffer layer to reduce substrate leakage current and raise the capability of vertical breakdown voltage. The highest breakdown voltage for the device with Lgd=60μm is 2760V, and the best BFOM is 604 MW/cm^2 for the device with Lgd=20μm. A drain current instability that is different from the current collapse due to surface and bulk traps is observed and explained.

中文摘要........................I
Abstract.......................II
致謝............................III
目錄............................V
圖目錄..........................VII
表目錄..........................IX
第一章 序論......................1
1.1前言:........................1
1.2文獻回顧與研究動機.............2
1.3研究方向簡介與論文架構..........8
1.3.1 研究方向簡介................8
1.3.2論文架構....................8
第二章 元件介紹及實驗設計...........13
2.1 氮化鋁鎵/氮化鎵材料介紹.........13
2.1.1 自發性極化效應...............13
2.1.2 壓電性極化效應...............14
2.2 基板的選擇.....................15
2.3 場平板結構(field plate)........15
2.4 元件隔離方式(isolation)........16
2.5 實驗設計.......................17
2.5.1 試片種類.....................17
2.5.2元件光罩設計...................18
第三章 光罩設計與元件製程.............22
3.1 增強型p-GaN/AlGaN/GaN HEMT設計流程..22
3.2源極/汲極區域之p型氮化鎵蝕刻...........23
3.3 歐姆接觸與金屬對準記號..............26
3.4 元件隔離區域.......................26
3.5 閘極金屬製作.......................27
3.6 p型氮化鎵自我對準蝕刻...............28
3.7 表面鈍化層.........................28
3.8 場平板和襯墊金屬....................29
第四章 元件量測結果分析.................33
4.1電壓-電流量測分析....................33
4.11 TLM測試元件量測....................33
4.12不同閘極結構的電壓-電流特性...........35
4.13正向與反向漏電流量測分析..............39
4.2 升溫特性分析.........................40
4.3 崩潰特性分析.........................42
4.31元件崩潰量測.........................42
4.32元件崩潰電流分析......................44
4.4 閘極下方電位浮動特性分析...............45
4.41 空乏型蕭基特閘極.....................45
4.42 增強型p型氮化鎵閘極..................50
4.42-1 閘極影響..........................51
4.42-2 汲極影響..........................54
第五章 結論與未來工作......................60
參考文獻.................................61

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