臺灣博碩士論文加值系統

本篇論文中，我們利用射頻磁控反應性濺鍍法沉積氧化鋅薄膜。通入參與反應的氣體為氬氣及氧氣的混合氣體，調整氣體流量以及比例，製程溫度與壓力，得到不同組成比例與結晶特性的薄膜，利用此非整數比特性以及前述的製程參數來最佳化所需要的薄膜，進而分別在ITO玻璃基板以及p型氮化鎵基板上製作p-i-n結構，測量其發光與吸光特性。同時，利用電腦模擬軟體來進行元件最佳化的工作，利用量測工具測量相關物理參數，帶入模擬軟體中，與實驗相互回饋，藉此達到元件最佳化的目的。最後，依照實驗以及模擬的最佳參數，製作p-i-n元件，並量測其電流－電壓特性以及電激發光特性。
在氧化鋅摻雜銅這層的分析中，我們先在15mTorr的製程壓力之下,以氧氣與氬氣的混和氣體，改變不同製程溫度藉以得到不同結晶特性與組成的薄膜。在材料性質方面，我們利用掃描式電子顯微鏡觀察薄膜表面；光學特性方面，利用UV穿透光譜量測在ITO玻璃上沉積的薄膜的穿透與吸收率，並換算成光能隙寬；利用光激發光量測其激發光波長，估計銅摻雜所造成的摻雜能階位置，進而證明銅摻雜造成的載子傳輸特性。
在氧化鋅摻雜鋁的n型透明導電薄膜分析中,我們分別在15以及20mTorr的製程壓力下，改變製程溫度沉積薄膜。利用掃描式電子顯微鏡觀察表面以及膜厚，同樣地，量測穿透及吸收率，並估計其光能隙寬。在電性方面，利用四點探針來量測片電阻，換算出電阻率，對薄膜特性最佳化。
利用上述最佳化的參數在p型氮化鎵以及ITO基板上製作p-i-n結構，量測其光激發光以及電激發光以及光吸收特性並量測其I-V，並由I-V推導理想因子，開路電壓及短路電流。
藉著此一研究，我們確定了銅摻雜在氧化鋅中造成的能階位置並成功製作出氮化鎵─氧化鋅異質接面p-i-n發光二極體以及UV太陽能電池。基於此結果，我們認為氧化鋅具有潛力應用於大面積光電元件的製作。

In this thesis, we deposited ZnO thin-film using RF-magnetron reactive sputtering. Argon and oxygen are used as the reactive gas source. We verified the mixture ratio, substrate temperature and total pressure to deposit different crystalline and composition thin-film. We optimized our thin-film quality according to the results of these process recipes. Moreover, we deposited thin-films on both ITO and p-GaN substrate in order to fabricate a p-i-n structure, measuring the light emission and absorption properties. Meanwhile, by using CAD ( Computer Aided Design ) tools, we optimized the device structure. We take the physical parameters we measured feedback into the simulation tools, leading our simulation more accurate. Finally, according to our best recipe, fabricate a p-i-n device. EL ( Electro-Luminescence ), PL ( Photo-Luminescence ) and I-V measurements are taken as the device characteristics.
In ZnO:Cu analysis, we deposited ZnO:Cu films at 15 mTorr. By using the mixture of Ar and O2 mixture, using various pressure and deposit our films. And we measure both optical and electrical properties of this film. Also, we observe surface morphology by SEM. And finally calculate the carrier transition behavior in this layer.
In ZnO:Al analysis, we deposited ZnO:Al films in both 15 and 20 mTorr. After that, we measure the optical and electrical properties. And optimize the electrical property. We found that in our system our optimize resistivity is around 2x10-2 ohm-cm.
According to the optimize recipe, we deposit ZnO films on both ITO and GaN substrate. I-V and EL and PV characteristics are taken as our focus measurements. By this research, we can advanced understand the role of copper in ZnO and the advantages of ZnO/GaN heterojunction diode. This is just a beginning; so many physical behaviors are still unknown. Due to this reason, we will take more effort on the advanced properties of ZnO and p-type TCO researching.

Chinese Abstract
English Abstract
Acknowledgement
Contents
Chap. 1 Introduction 1
1.1 Introduction of TCO 3
1.2 p-type and n-type ZnO 4
1.3 p-n structure device 5
1.4 copper doped ZnO 8
1.5 Our moltivation 12
1.6 Applications of ZnO-based transparent devices 13
Chap. 2 Mechanism 15
2.1 Thornton model 15
2.2 role of copper in ZnO 19
2.3 Indirect Recombination of carrier 21
2.4 PN and PIN junction operation 23
2.4.1 I-V characteristic 24
2.4.2 I-V characteristics 25
2.5 ZnO/GaN heterojunction band structure……………………………….25
Chap. 3 Experiment………………………………………26
3.1 Our device structure……………………………………………………26
3.2 The metal mask design…………………………………………………29
3.3 Process flow…………………………………………………………….31
3.4 Process facilities………………………………………………………...32
3.5 ZnO:Cu process conditions……………………………………………..33
3.6 ZnO:Al process conditions……………………………………………..34
3.7 Contact forming………………………………………………………...35
Chap. 4 Result and Discussion…………………………...36
4.1 ZnO:Cu analysis………………………………………………………...37
4.1.1 surface morphology…………………………………………………...37
4.1.2 the optical properties of ZnO:Cu films………………………………..42
4.2 ZnO:Al analysis………………………………………………………….45
4.2.1 surface morphology………………………………………………….....45
4.2.2 XRD results………………………………………………………….....48
4.2.3 Electrical properties…………………………………………………….49
4.2.4 Optical properties……………………………………………………….50
4.3 ITO/ZnO:Cu/ZnO:Al M-I-S device characteristics………………………52
4.4 p-GaN/ZnO:Cu/ZnO:Al p-i-n device characteristics……………………. 54
4.5 The innovation: HBT-LED……………………………………………….55
Chap. 5 Conclusion …………………………………………58

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