本論文透過在金屬汲極端加入p型氮化鎵來提升高電子遷移率電晶體之動態導通電阻特性，並使用了四種不同的磊晶結構，主要差別為p-GaN摻雜濃度的差異和加入氮化鋁作為蝕刻阻擋層之結構。
在p-GaN下方插入一層AlN對於p-GaN蝕刻的影響在本實驗中得到了充分的探討，雖無法如預期一般得到非常好的蝕刻選擇比，但對於蝕刻的控制還是可以有一定程度的掌握，所以在良率和電性上還是有所提高。
三種鎂濃度摻雜之HEMT的臨界電壓由低至高為1.57 V、1.66 V和2.17 V，另外在p-GaN下方加入AlN之HEMT則為0.51 V。而p-drain HEMT在基本電性方面皆與一般之HEMT有極大的相似，表示加入p-drain結構並不會使電性變差，反而在可靠度方面有所提升。在動態導通電阻量測上，p-drain HEMT在元件關閉狀態時因有電洞注入讓陷阱中的電子脫離，所以具有抑制電流崩潰的能力，而在觀察水平崩潰電壓量測後，發現崩潰電壓似乎與p-drain的位置有一定的影響。最後，在高溫反向偏壓測試上，p-drain HEMT在長時間的應力下，亦展現了良好特性，期待未來能應用在高功率領域中。

In this work, the dynamic on-resistance characteristics of high electron mobility transistors are improved by adding p-type gallium nitride to the metal drain terminal, and four different epitaxial structures are investigated. The main differences are p-GaN doping concentration and with/without aluminum nitride as an etching stop layer.
The effects of inserting a layer of AlN under the p-GaN for the critical p-GaN etching has been examined. Although the etching selectivity is not as good as expected, the control of etching can still be improved as indicated by the yield and electrical characteristics.
The threshold voltages of the three types of HEMTs doped with different magnesium concentrations are 1.57 V, 1.66 V and 2.17 V, while that of the HEMTs with AlN added below p-GaN is 0.51 V. The DC electrical characteristics of p-drain HEMTs are very similar to those of conventional HEMTs, which means that the addition of p-drain structure does not deteriorate the electrical characteristics, but the reliability can be improved. From the dynamic on-resistance measurement, current collapse is suppressed in the p-drain HEMT because the electrons are detrapped by the hole injection in the blocking state. Finally, from the preliminary high temperature reverse bias test, the p-drain HEMT maintains normal characteristics after stress.

中文摘要.......................................i
Abstract......................................ii
目錄...........................................iv
圖目錄.........................................vii
表目錄.........................................xi
第一章 序論.....................................1
1.1前言......................................................1
1.1.1氮化鎵材料特性介紹.......................................1
1.2文獻回顧..................................................4
1.2.1氮化鋁鎵/氮化鎵高電子遷移率電晶體.........................4
1.2.2 P型氮化鎵閘極高電子遷移率電晶體..........................5
1.2.3氮化鎵高電子遷移率電晶體動態導通電阻.......................6
1.3研究方向與架構.............................................8
1.3.1研究方向................................................8
1.3.2論文架構................................................9
第二章 原理簡介..............................................10
2.1氮化鎵材料特性............................................10
2.1.1自發性極化(spontaneous polarization)...................10
2.1.2壓電極化(piezoelectric polarization)...................11
2.2 P型氮化鎵覆蓋層(p-GaN cap layer).........................11
2.3 P型氮化鎵蝕刻製程........................................12
2.4 P型氮化鎵閘極接觸........................................14
第三章 元件製程..............................................15
3.1晶圓之磊晶結構............................................15
3.2元件製作流程..............................................17
3.2.1試片清潔................................................17
3.2.2對準記號蝕刻(alignment mark formation)..................18
3.2.3氧離子佈值隔離(oxygen ion implantation isolation).......19
3.2.4 ITO薄膜沉積(ITO deposition)............................20
3.2.5 ITO薄膜蝕刻(ITO etching)...............................20
3.2.6 p-GaN蝕刻(p-GaN etching)...............................21
3.2.7源極/汲極歐姆接觸金屬(source/drain ohmic contact)........22
3.2.8襯墊金屬(pad metal).....................................23
3.2.9 鈍化層沉積(surface passivation)........................24
3.3元件尺寸與俯視圖...........................................26
3.3.1元件規格................................................26
3.3.2元件俯視圖..............................................28
3.4氮化鋁蝕刻測試.............................................30
3.4.1蝕刻深度................................................30
第四章 元件量測與結果分析......................................33
4.1 TLM(transfer length method)測試結構量測...................33
4.1.1 2DEG TLM量測...........................................33
4.1.2 ITO/p-GaN TLM量測......................................33
4.1.3相同晶圓下之汲極電流對閘極電壓特性曲線(Id-Vg)..............39
4.1.4相同晶圓下之汲極電流對汲極電壓特性曲線(Id-Vd)..............44
4.1.5相同晶圓下之動態導通電阻(Dynamic Ron).....................47
4.1.6相同晶圓下之水平崩潰電壓量測(Breakdown)...................52
4.1.7相同晶圓下之高溫反向偏壓測試(HTRB)........................55
第五章 結論與未來工作.........................................58
參考文獻.....................................................59

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