半極性與非極性氮化鎵之寬能隙材料及光電元件研究-子計畫一：半極性與非極性氮化鎵半導體材料元件磊晶成長

Abstract

非極性和半極性氮化鎵半導體由於在成長方向上不具內建電場，因此在能帶結構上具平帶特性可使電子、電洞波函數在空間中復合機率高，因此在理論上發光效率可以比傳統具極性之發光元件還來得高，故在利用其製作高效率發光元件上極具潛力。此外由於非極性和半極性三族氮化物具相當強的偏振光特性，故在光性應用上十分廣泛。本計畫主要目的為成長高品質非極性和半極性三族氮化物相關材料及元件。利用有機金屬氣相沈積系統成長非極性和半極性發光二極體並以降低螺旋差排及疊差密度為首要目標，主要利用之技術如利用非極性氮化鎵模板上製作奈米柱，再利用側向成長的方式製作出高品質磊晶層、調整適當之磊晶參數和磊晶結構優化，以增加元件之發光性能，並製作出偏光效率良好之元件。另外在製程方面，計劃運用了基板圖案化後再成長高品質非極性和半極性氮化鎵磊晶層。再者，我們可以運用布拉格反射結構於非極性或半極性面射型雷射之共振腔結構中，再藉由本研究室暨有的光學和電學設備進行量測、分析非極性或半極性面射型雷射之高效能元件及物理特性。

Unlike conventional c-plane devices, non-polar and semi-polar III-nitride semiconductor materials are free of polarization related electric fields along the growth direction. In theory, the emission efficiency of non-polar and semi-polar devices would be better than that of c-plane devices. In addition, due to the anisotropic structure, non-polar and semi-polar devices have much potential in optical applications. Epitaxial growth method of devices related to non-polar and semi-polar GaN with high quality was proposed in this project. With the goal of achieving the low threading dislocations and stacking faults density, the high efficient non-polar and semi-polar light emitting diodes would be grown by Metal-Organic Chemical-Vapor Deposition (MOCVD). Main techniques include epitaxially lateral over growth by nanowire on non-polar GaN template, suitable epitaxial parameters and optimization epitaxial structure. For process, patterned sapphire would be proposed to non-polar and semi-polar GaN with high quality. Furthermore, distributed bragger reflector (DBR) structure could be used to application of non-polar and semi-polar vertical cavity surface emitting laser (VCSEL). Combining with optical and electrical measurement instrument, the high efficient performances and physical characteristics of non-polar and semi-polar VCSEL would be measured and identified.