於本論文中，將高功率氮化鎵p-i-n二極體利用金屬有機化學氣相沉積法(MOCVD)成長於圖形化藍寶石基板(PSS)上，製作出準垂直式氮化鎵p-i-n二極體。當操作於順向偏壓下，在高階注入時會有電導調變現象而導致有較低的順向串聯電阻，當施加逆向偏壓時，氮化鎵p-i-n二極體的本質層具有耐壓能力，故可以承受高電壓。
利用不同磊晶晶圓之本質層濃度及厚度來製程元件，於順偏下，本質層厚度較薄與濃度較高之磊晶結構，在相同的元件結構與製程方法下，具有較低的順向電壓及特徵導通電阻。為了提高元件逆向偏壓特性，利用邊緣終結方法的二階平台型結構、場板結構和整合二階平台型與場板結構來降低漏電流與提高崩潰電壓。而在磊晶結構之本質層5微米和濃度1×1016 cm-3之磊晶片及整合二階平台型與場板結構有最低的特徵導通電阻0.59 mΩ-cm2 及超過800 V的崩潰電壓，而得到最佳巴利加值(Baliga’s Figure of Merit, BFOM)大於1 GW/cm2。最後，鍍鋁於平台結構層表面以遮蔽元件於順向偏壓時所發出之紫外光，避免紫外光對封裝樹脂的破壞與脆化，進而達到元件的穩定性。

In this study, high power GaN p-i-n diodes are grown on pattern sapphire substrates (PSSs) by metal organic chemical vapor deposition (MOCVD) and fabricated to quasi-vertical structure. The intrinsic layer (i-layer) has conductivity modulation in high level injection resulting in decreasing the forward series resistances at forward bias. When a negative bias is applied, i-layer of GaN p-i-n diode could support high reverse voltage.
Using the concentration and thickness of i-layer with different epitaxial wafers fabricates devices. The thinner thickness and higher concentration of the i-layer are, the lower forward voltage (VF) and specific on-resistance (RONA) will be. In order to improve reverse characteristics of device, using two-step, field plate and integration of two-step and field plate structures with edge terminations can reduce the leakage current and enhance the breakdown voltage at reverse bias. The thickness 5 μm and concentration 1×1016 cm-3 of i-layer with integration of two-step and field plate structure has the lowest specific on-resistance of 0.59 mΩ-cm2 , and breakdown voltage is over 800 V. The corresponding Baliga’s Figure of Merit (BFOM) is over 1 GW/cm2. Finally, depositing aluminum along surface of mesa shades the ultraviolet from device at forward bias, and avoiding the epoxy of package be broken to achieve better reliability of device.

摘要 I
Abstract II
誌謝(Acknowledgements) III
Contents IV
List of Figures VI
List of Tables IX
Chapter 1 Introduction 1
1-1 Background of Gallium nitride (GaN) 1
1-2 p-i-n diodes 3
1-3 GaN on sapphire substrate 5
1-4 Ultraviolet of GaN p-i-n diodes 6
1-5 Research Motivation 7
Chapter 2 Fundamental Principles 9
2-1 Mg-doped of p-GaN with MOCVD 9
2-2 Abrupt one-dimensional of p-i-n diode 10
2-2-1 Forward currents of p-i-n diodes 11
2-2-2 Reverse bias of p-i-n diodes 13
2-3 Punch-through diode 15
2-4 Edge terminations 17
2-4-1 Two-step structure 18
2-4-2 Field plate 19
2-5 Baliga’s figure of merit for power devices 21
Chapter 3 Experimental Procedure 23
3-1 Fabrication processes of GaN p-i-n diodes 23
3-2 Experimental details 27
3-3 Measurement systems 36
Chapter 4 Result and Discussion 37
4-1 Different epitaxial structure under SEM 37
4-2 Contact resistance of Ni/Au and p-GaN with CTLM 41
4-3 Capacitance-voltage characteristics of the GaN p-i-n diodes 45
4-4 Effects of two-step structure of the GaN p-i-n diodes 49
4-5 Effects of field plate structure of the GaN p-i-n diodes 56
4-6 Effects of integration with two-step and field plate of the GaN p-i-n diodes 63
4-7 Ultraviolet confinement 71
Chapter 5 Conclusions 73
References 75

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