製造點狀圖形化a-plane藍寶石基板用以成長氮化鎵發光二極體

Abstract

本研究為改善氮化鎵發光二極體的性質，針對a-(11-20) plane藍寶石基板提出新的製程進行圖形化處理，接著送入有機金屬氣相磊晶系統(MOCVD)進行發光二極體的磊晶。藉由控制蝕刻參數，同時改變基板圖案的深度與傾斜面的角度，最佳化光取出效率(LEE)與內部量子效率(IQE)。比較傳統的藍寶石基板(A-Planar)與圖形化藍寶石基板(A-PSS)：圖形化藍寶石基板磊晶後表面平整度較高，蝕刻孔較少，XRD ω-scan半高寬值較低，由TEM觀察貫穿差排數量明顯下降。在20mA下，output power提升了68.2%。

This study is to improve the performance of GaN-based LED. The effects of patterned sapphire substrate were investigated. A new process is proposed to pattern a-plane sapphire substrate, follow by the growth of LED structures. By the control of etching parameters, different pattern depth and inclined angle can be achieved, in the meanwhile, optimize the light extraction efficiency and internal quantum efficiency. Compare dot pattern sapphire substrate (A-PSS) with the conventional sapphire substrate (A-Planar) : A-PSS get more flat region, less etching pit density, better ω-scan FWHM value. Besides, according to TEM analysis, threading dislocation density is decrease obviously. For output power, at 20mA current drive, patterned sapphire substrate was 68.2% lager than conventional sapphire substrate.