本文中我們利用掃描式近場光學顯微鏡技術，檢測圖形化藍寶石基板上成長的 GaN 薄膜的缺陷分布。因薄膜缺陷能隙與薄膜本身能隙不同，而穿透光強度與樣品材料能隙有關，經由不同波長光源檢視樣品的穿透光強度分布，即可由此分布觀察到缺陷的分布狀況。我們觀察到有凸起截頂圓錐圖形藍寶石基板上所製作的 GaN 薄膜，在上下交界及圖形上方有明顯的缺陷，而有凹入圓錐狀圖形藍寶石基板上所製作的薄膜，在單一邊上下起伏附近容易產生缺陷，但圖形上方仍可成出良好的薄膜，且此種凹洞基板再配合成長時加 SiO2 遮罩後，在其上方可以長成更好品質的薄膜。

We report the investigation of the defect distribution of GaN grown on patterned sapphire substrates by using a scanning near-field optical microscope (SNOM). A He-Cd laser (325 nm) or a green-light semiconductor laser (532 nm) was used as the light source in the SNOM system. The transmission SNOM images can be used to study the distribution of defects of a GaN LED structure on a patternned sapphire substrat. We found that the defects are located near the edge of the recess holes on sapphire, and the quality of the GaN thin fi lm can be improved by adding random SiO2 blocking masks.