臺灣博碩士論文加值系統

本研究主要是以III-V族化合物半導體之氮化鎵(GaN)來製作n型通道金半場效電晶體(n-channel MESFET)，相較於其他半導體材料，氮化鎵具有寬能隙(約3.4 eV)及高崩潰電壓等特性，因此氮化鎵元件將有承受高電壓及大電流之能力。
首先，我們選用環型傳輸線模式(CTLM)來量測金半接面之歐姆接觸(Ohmic Contact)特性，歐姆接觸的好壞將直接影響元件特性之表現，實驗結果發現Al/GaN於700℃、5 min的退火條件下能有效降低特徵電阻；至於蕭基接觸(Schottky contact)，則是利用Au/GaN來探討蕭基能障之整流特性。
接著再以電子束(E-beam)蒸鍍技術製作Al/Ti與Au/Pt雙層金屬電極，分別探討其對(MESFET, Metal-Semiconductor Field Effect Transistor)元件歐姆接觸、蕭基接觸特性之影響，並進一步製作嵌入式閘極(Recessed-gate)元件，以逐步改善氮化鎵金半場效電晶體(GaN MESFET)之電性。

This study is primarily to fabricate a n-channel metal-semiconductor field-effect transistor (MESFET) with GaN III-V compound semiconductor. GaN is provided with wider band-gap and higher breakdown voltage than other semiconductor materials.
In order to improve the ohmic contact progressively, the circular transmission line method (CTLM) is used to measure contact resistance. The behavior of ohmic contact will influence directly the device characteristics. The lowest specific contact resistance of Al/GaN is obtained by annealing at 700°C for 5 min. Au/GaN is selected to study the rectification characteristic and Schottky barrier height.
To further improve the MESFET characteristics, single-layer metal electrode is instead of double-layer structure. The recessed-gate MESFET is also fabricated to progressively improve the device characteristics.

誌謝 ii
摘要 iii
ABSTRACT iv
表目錄 vii
圖目錄 viii
1. 緒論 1
1.1研究背景 1
1.2研究目的 2
2. 理論基礎 4
2.1 金屬與半導體歐姆接觸 8
2.2 金屬與半導體蕭基接觸 10
2.3 嵌入式閘極(Gate)和蕭特基接觸製作 11
2.4 Photoluminescence(PL)原理 12
2.5 電子槍(E-Gun)蒸鍍操作原理 13
2.6 MESFET元件操作原理 15
3. 實驗方法與步驟 22
3.1 n型氮化鎵之霍爾量測及光激螢光頻譜量測 22
3.2 n型氮化鎵二次離子質譜儀(SIMS)量測 25
3.3 n型氮化鎵之歐姆與蕭基接觸研究 26
3.3.1 歐姆接觸電極製作 27
3.3.2 蕭基接觸電極製作 27
3.4 氮化鎵金半電晶體(MESFET)之結構與製作 28
3.4.1 MESFET源極、汲極電極製作 28
3.4.2 MESFET閘極電極製作 29
3.5 電子槍(E-Gun)蒸鍍雙層金屬氮化鎵金半電晶體(MESFET)之製作 30
3.6 氮化鎵金半場效電晶體嵌入式閘極(Recess Gate)之製作 31
4. 結果與討論 34
4.1 n型氮化鎵鍍鋁(Al)退火(Anneal)不同溫度 34
4.2 n型氮化鎵鍍金(Au)退火(Anneal)不同溫度 43
4.3 氮化鎵金半場效電晶體(MESFET)電性討論 47
5. 結論與未來展望 51
參考文獻 53
自傳 55

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