本研究是使用磊晶側向成長法(Epitaxial Lateral Overgrowth, ELOG)的技術，利用有機化學氣相沈積法(metal organic chemical vapor deposition, MOCVD )來成長氮化鎵的膜，研究不同的mask fill factor對氮化鎵特性的影響及穿遂差排的影響，從SEM照片發現在同樣的成長條件下，當mask fill factor等於1的時候氮化鎵幾乎已經成為膜，但是當mask fill factor等於5時卻還是獨立的錐狀體，在X-ray的rocking curve中發現不同的mask fill factor在c軸方向的偏斜程度也不一樣，在光學分析的結果是比較一致的，主要發光波長都為3.4eV在Yellow Luminescence的中心位於2.3eV。在穿透式電子顯微鏡(TEM)的分析中，有明顯的看見差排彎曲的現象，這也達到這個製程的目的。

　The optical performance of a GaN blue-light emitting diode is greatly influenced by the density and distribution of threading dislocations, which in turn strongly depend on the ratio of mask to window width during Epitaxial Lateral Overgrowth (ELOG). Thus we study the dependence of microstructure and optical property evolution on the spatial distribution of the defects in the ELOG GaN films by varying mask to window width ratio. The window width is maintained at 5μm and the ratio is varied from one to five. We employ a two-step ELOG method to fabrication GaN by Metalorganic chemical vapor deposition (MOCVD), where SiO2 as the mask was grown on low-temperature GaN as the buffer and seed layer. The patterns were square dot array and developed by conventional photolithography method, where the ELOG GaN stripes on SiO2 were arranged along the directions of the underlying GaN. X-ray rocking curves show that all the resulting films are of excellent epitaxial quality with non-uniform strain distribution, which was a function of the mask ratio and determines the spatial distribution of threading dislocations. The detailed GaN island evolution was also revealed by scanning electron microscopy. Photoluminescence and cathodoluminescence examine the origins of UV and yellow emissions, which can be explained by defect generation as examined by transmission electron microscopy. The mechanism for impeding threading dislocations is discussed.

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