以氮化鎵為基礎之發光二極體(GaN - based Light Emitting Diode, LED)目前主要以藍寶石(Sapphire)為基板，由於藍寶石基板熱傳導能力不佳，因此在高功率的操作下會有散熱的問題，而本論文主要在thin - GaN發光二極體的u - GaN製作結構，並以銅為基板，藉由不同線寬同週期的表面微米光柵結構來探討結構線寬的變異對光萃取效率及光型之影響。
本研究中模擬配合製成去分析在thin - GaN發光二極體之u - GaN層製作不同線寬但結構週期相同的光柵結構，探討其光萃取效率上的差異，接著在計算各個結構的光型圖。在製程方面，我們利用乾式蝕刻(Dry Etching)及濕式蝕刻(Wet Etching)製程來製作微米等級的表面氮化鎵光柵結構，透過電致發光的量測，得知線寬分別為3.5、5.5、7以及9 ?m的一維(one dimension)表面光柵結構之thin - GaN 發光二極體，相較於平面的thin - GaN 發光二極體，在光萃取效率上分別有45.5 %、59.9 %、69.1 %及72.7 %的提升。在光型方面，我們可知表面光柵結構可將thin - GaN發光二極體原本光強會隨角度提升而下降的朗柏遜光型，調製為與正向夾角± 60°內光強仍維持在88 %以上的均勻光型，因此可知微米等級的表面光柵結構之斜面可以降低內部全反射的效應，有效的提升在空氣端高頻空間的光萃取量，進而提升整體的光萃取效率。

Because the low heat conductivity of sapphire substrate, so GaN - based light emitting diodes are inappropriate for high - power injection. In this thesis, we applied different line - width of grating structure on u - GaN surface, and to discuss the influence of light extraction efficiency and light pattern.
We fabricated different micro - grating structure by using dry etching and wet etching. Through EL measurement, we found that the light extraction efficiency of different line - width 3.5、5.5、7 and 9 ?m, which enhanced 45.5 %、59.9 %、69.1 % and 72.7 %, respectively. We also found that the grating structure could modulate light pattern of thin - GaN LED from lambertian emission pattern to a uniform emission pattern. In this research, we will analysis the influence of light extraction and light pattern for different grating structure by simulation.
The micro - grating structure of trapezium and triangle can increase extractive area of light from the bevel. The bevel of grating structure can reduce the total internal reflection effect, and improve light extraction efficiency.

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