臺灣博碩士論文加值系統

以氮化鎵為基底的材料已成功應用於短波長雷射二極體，發光二極體及紫外光光檢測器。在本實驗中，我們已成功的使用有機金屬氣相沈積法把氮化鎵磊晶膜生長在三氧化二鋁基板上。並對生長氮化鎵磊晶膜前之氧化鋁基板預熱處理和氮化鎵緩衝層之生長溫度以及氮化鎵磊晶膜的生長溫度等參數進行研究。根據77K的光激發光譜、X光散射測量、掃瞄式電子顯微鏡的結果，瞭解氮化鎵的基本特性，並利用上述方式，生長更好的氮化鎵磊晶膜。在本實驗中，發現氧化鋁基板之預熱處理為影響單晶品質及表面平整度的重要參數。根據實驗的結果，我們針對黃光區及施體受體對的成因做了深入的研究及探討。

The materials based on GaN have successfully developed on short-wavelength laser diodes (LDs), light-emitting diodes (LEDs) and ultraviolet photodetector. In this study, GaN epitaxial layers have been successfully grown on sapphire substrates. We used several methods including the pre-baking treatment for sapphire substrates before growing epilayer, the growth temperature of buffer layer and the growth temperature of GaN epilayer to study it. From the results of the photoluminescence (PL) measured at 77K, the X-Ray diffraction measurement, SEM cross sectional views to realize the characteristic and we get a better qualities of GaN epilayers after using the foregoing methods. In this study, the pre-baking treatment for sapphire substrates can influence the quality and morphology of GaN epilayers. According to the results of the experiments, we study the mechanisms of yellows luminescence and donor-acceptor pair (DAP).

CONTENTSI
LIST OF FIGURESIV
ABSTRACTVII
1.INTRODUCTION1
1.1 Evolutions and Applications of Ⅲ-Ⅴ compound Light EmittingDiode 1
1.2 Materials for Blue LEDs 5
1.2.1 SiC Blue LEDs 5
1.2.2 ZnSe Blue LEDs 6
1.2.3 GaN Blue LEDs 7
1.2.4 Blue Organic LEDs 9
1.3 Short Wavelength Light Emitting Diode Based on Ⅲ-Ⅴ
Nitride Materials10
1.4 Growth for GaN-based Compound Semiconductors12
(a) Considerations of the Appropriate Substrates13
(b) Growth for p-type GaN 14
2.EXPERIMENTS17
2.1 Growth System of MOCVD17
2.1.1 Single Hot Zone and Cold Wall System 17
2.1.2 Simplicity, Flexibility and Versatility 18
2.1.3 Halide Free18
2.1.4 Capability of Multiple Heterostructures 19
2.1.5 High Temperature19
2.1.6 Low Pressure19
2.2 Growth System Design20
2.2.1 Gas Handling System20
2.2.2 Reaction Chamber Design 21
2.2.3 Heating System22
2.2.4 Exhausted System22
2.2.5 Safety Equipment Considerations 23
2.3 Substrate Preparation24
2.4 Growth Processes24
2.5 Evaluation of GaN Epilayers26
3.RESULTS AND DISCUSSION27
3.1 Optical Properties of GaN Epilayers27
3.2 Effect of Sapphire Pre-Baking at 1000℃29
3.2.1 PL Properties29
3.2.2 X-Ray Measurements30
3.2.3 SEM Analysis30
3.3 Effect of Various Sapphire Pre-Baking Temperature32
3.3.1 PL Properties32
3.3.2 X-Ray Measurements33
3.3.3 SEM Analysis34
3.3.3 SIMS Depth Profiles and Analyses34
3.4 Effect of Sapphire Pre-Baking at 1200℃37
3.4.1 PL Properties37
3.4.2 X-Ray Measurements38
3.4.3 SEM Analysis38
3.5 Effect of the Flow Rate of TEGa 40
3.5.1 PL Properties40
3.5.2 SEM Analysis41
3.6 Effect of the Flow Rate of Ammonia 43
3.6.1 PL Properties 43
3.6.2 X-Ray Measurements 44
3.6.3 SEM Analysis44
3.7 Effect of chamber pressure on GaN Growth46
3.7.1 PL Properties46
3.8 Effect of additional hydrogen on GaN growth 48
3.8.1 PL Properties 49
3.8.2 X-Ray Measurements50
3.8.3 SEM Analysis 50
3.9 Effect of Various Sapphire Pre-Baking Temperature
(Growth Without Additional H2) 51
3.9.1 PL Properties51
3.9.2 X-Ray Measurements52
3.9.3 SEM Analysis52
3.9.4 DCXD rocking curves Measurements52
3.10 Effect of the Temperature of Nitridation and Buffer Layer55
3.10.1 PL Properties56
3.10.2 X-Ray Measurements57
3.10.3 SEM Analysis58
3.11 Growth Temperature of GaN Epilayer59
3.11.1 PL Properties59
3.11.2 X-Ray Measurements60
3.11.3 SEM Analysis61
3.12 Other Analyses in Our Experiments62
3.12.1 X-Ray Measurements62
3.12.2 AES Analysis62
3.12.3 XPS Analysis63
3.13 Possible Mechanisms of Yellow Luminescence64
3.14 Mechanisms of DAP and YL in Our Experiments66
4.CONCLUSIONS68
REFERENCES120

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