近年來，由於無線通訊技術的發達，例如手機、無線網路、無線充電及車用感應器…等；使得高頻及高功率電晶體的需求增加，氮化鎵高電子遷移率電晶體(GaN-based HEMTs)，優越的材料特性，成為近年來非常受矚目的研究重點。AlGaN/GaN HEMTs具有高電子遷移率及在高電場下可維持高電子飽和速度，非常適合毫米波的應用。另外，為了降低成本及未來可能與CMOS電路作整合，將GaN元件製作於矽(Si)基板上已成為趨勢，元件的特性也已經有顯著的成果，然而，AlGaN/GaN HEMTs的可靠性(reliability)仍然是個問題。
本論文著重於矽基板(Si substrates)之InAlN/GaN HEMTs之高頻元件設計及分析，氮化銦鋁/氮化鎵(InAlN/GaN)接面具備晶格匹配特性，可望提高元件的可靠性，且在較薄的InAlN厚度下，仍可維持高濃度的二維電子氣通道，對電晶體的高頻特性非常有幫助。
本論文研究之矽基板InAlN/GaN HEMTs元件中，掘入式T型閘極結構的高頻特性表現，f_T可達50GHz以上，f_max可達100GHz以上。利用線型閘極加入蕭特基源極/汲極外延層結構，亦可成功地提升高頻特性。我們藉由高頻等效電路模型對元件進行分析，根據等效模型參數，指出高頻特性主要是被寄生效應所限制，所得到的結果也可以幫助我們了解，如何進一步改善元件的特性及InAlN/GaN 成長於矽基板上的磊晶結構。

In recent years, the wireless technology has been used widely for different applications such as mobile phones, wireless charging, and automotive sensors. This leads to an exponential increased demand of high frequency and high power transistors. GaN-based devices, owing to the superior material properties, have attracted significant attentions and become a popular research topic over the past decade. The AlGaN/GaN high electron mobility transistors (HEMTs) with an excellent mobility and high saturation velocity under a high electric field are suitable for millimeter wave applications. More recently, these devices fabricated on the silicon substrate with lower cost and possibility to integrate with CMOS devices showed significant progress in device characteristics. However, the transistor reliability is still an issue.
This thesis focuses on design and analysis of the high-frequency device of InAlN /GaN HEMTs on the Si substrates. The lattice-matched InAlN/GaN interface is expected to improve the device reliability issue. The high carrier density in the 2DEG channel can also enhance the transistor frequency response. The fabricated devices show a best f_T and f_max up to 50 GHz and 101 GHz respectively with a gate-recess structure. The devices with Schottky drain/source extension also result in improved high frequency performance. We analyze the devices in details by using the small-signal equivalent circuit model. Based on the analysis of the equivalent circuit model parameters, the dominant parasitic effects to limit the device RF characteristics have been identified. The obtained results can be used to understand how to further improve the device performance regarding the device fabrication and the epitaxy structure of the InAlN/GaN on the Si substrate.

誌謝....................................................i
Abstract...............................................ii
摘要..................................................iii
目錄...................................................iv
圖表目錄...............................................vii
表格目錄................................................xi

第一章 簡介..............................................1
1.1 研究動機.............................................1
1.2 論文架構.............................................1

第二章 氮化鎵材料與異質介面場效電晶體......................2
2.1 材料特性之比較.......................................2
2.1.1 寬能隙半導體.......................................2
2.1.2 電子遷移率及飽和速度................................3
2.2 InAlN/GaN異質介面場效電晶體..........................4
2.2.1 氮化物阻障層(Barrier Layer)之比較..................4
2.2.2 Interlayer及緩衝層................................7
2.2.3 元件結構及操作原理.................................8
2.3 高頻InAlN/GaN異質介面場效電晶體......................10
2.3.1 短通道效應(Short channel effect)..................11
2.4 本章總結............................................14

第三章 元件製程.........................................15
3.1 黃光微影製程(PhotoLithography)......................15
3.2 元件隔離平台(Mesa isolation)........................17
3.3 歐姆接觸(Ohmic contact).............................18
3.3.1 InAlN表面處理.....................................19
3.3.2金屬層蒸鍍.........................................19
3.3.3高溫熱退火處理(Rapid Thermal Annealing)............20
3.3.4 Transfer Length Method (TLM).....................21
3.4 蕭特基閘極製作(Schottky gate).......................23
3.4.1 線型閘極加入源極/汲極外延層(SD Extend).............24
3.4.2掘入式(Gate Recessed) T型閘極......................26
3.5 鈍化層製作(Passivation).............................28
3.6 源極區間電阻(Source Access Resistance)量測..........30
3.7 本章總結............................................31

第四章 元件模型分析.....................................32
4.1 高頻S參數量測.......................................32
4.2 外部參數萃取及去嵌入(De-embedding)...................33
4.2.1開路及短路測試元件萃取法............................33
4.2.2 Cold-FET量測元件萃取法............................35
4.3 高頻RF元件小訊號等效模型建立及分析....................40
4.3.1 Y參數分析(Y-Parameter Analysis)...................41
4.3.2 模型參數萃取(Model Parameter Extraction)..........43
4.4 本章總結............................................46

第五章 量測結果與比較....................................47
5.1元件描述(Device Description).........................47
5.2 0.1μm 線型閘極元件量測結果與分析.....................49
5.2.1 直流量測結果......................................49
5.2.2 高頻量測結果......................................50
5.2.3 短通道效應討論....................................51
5.2.4 延遲時間分析......................................52
5.2.5 元件等效模型分析..................................55
5.3 0.1μm T型閘極元件量測結果與分析......................59
5.3.1 直流量測結果......................................59
5.3.2 高頻量測結果......................................61
5.3.3 量測結果比較......................................63
5.3.4 元件等效模型分析..................................64
5.3.5 基板效應模擬分析..................................68
5.4 本章總結............................................69

第六章 總結.............................................70
6.1 總結(Conclusion)...................................70
6.2 未來工作(Future work)...............................71
References.............................................72

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