利用選擇性缺陷填補法使得氮化鎵磊晶層品質改善的研究

Abstract

近年來，在半導體元件中，三五族材料的寬能隙特性引起專注並扮演重要的角色。而在固態照明的應用中，氮化鎵材料的發光二極體吸引大家的目光。此外，氮化鎵材料的其他應用也廣為人知，例如：全彩發光二極體背光顯示器、白光發光二極體以及藍光雷射。而發光二極體亟需改善輸出光功率。為了製作高效率發光二極體，與高品質、低缺陷密度的氮化鎵磊晶層有關。過去，已經證實選擇性填補缺陷方法有效的減低缺陷密度並可提高發光二極體特性。在本論文中，我們利用旋轉塗佈將二氧化矽奈米小球填補於缺陷孔洞，簡單化選擇性缺陷填補方法且達到製作高效率發光二極體的目的。經由光激發光與電激發光的分析，證實此方法可以有效提高氮化鎵磊晶層品質。

In recent decades, the III-nitrides become an interesting class of wide band-gap materials and play an important role in semiconductor devices. GaN-based light emitting devices have attracted great attention in last decade due to its importance in solid state lighting applications. The GaN-based device are full color LED displays, white LEDs and high capacity storage devices. However, GaN-LEDs still require further improvement of optical output power. To successfully fabricate high efficient LED depends on the high quality GaN epilayer with low defect density. In previous work, we demonstrated that the defect selective passivation method could reduce defect density and enhance LED performance. In this thesis, we simplify the process of defect selective passivation technique by spin-coating silica nanospheres on GaN surface to block the propagation of dislocations. Moreover, we apply defect selective passivation technique to fabricate high efficient LED. The analysis of photoluminescence, cathodoluminecence and electroluminescence show the crystal quality of GaN epilayer is improved.