以氫化物氣相磊晶技術在獨立式氮化鎵基板上再成長氮化鎵厚膜

Abstract

本論文研究熱退火表面處理方法及再成長磊晶參數。經過雷射剝離技術的獨立式氮化鎵基板，直接再成長氮化鎵厚膜會發生微裂痕情形。從PL 及CL 量測分析得知，主要原因為再成長厚膜與基板介面之間應力太大以及基板表面雜質濃度過高。在不同的熱退火條件中，在氨氣加氫氣、溫度1100 度時的熱退火條件，具有蝕刻的效果，再利用SEM 發現熱退火後的基板表面有佈滿六角錐狀類似圖案氮化鎵的形貌。也因為這兩種結果，後續再成長氮化鎵厚膜利用PL、CL、AFM 量測儀器所量測到的值，證明經過熱退火處理後的氮化鎵厚膜會有效地降低介面應力及缺陷密度。在後續再成長磊晶參數方面，去調變不同的參數做比較，利用PL、CL、AFM、XRD 量測分析，得到高HCl 流量、高壓、高溫、純氫環境下生長的氮化鎵厚膜有較好的磊晶品質。

In this work, we study surface treatment of thermal annealing and re-grown of GaN thick films. The free-standing GaN substrates by laser lift-off technology, direct regrowth of GaN thick films will take place crack situation.Examine and analysis from PL and CL amount that learns, the main reason is that the stress between thick film and substrate surface is too large and the substrate surface impurity is too high. In different condition of thermal annealing, the best condition is NH3+H2 and 1100oC , utilize SEM to find the substrate surface has shape looks of pattern GaN . Because of these kinds of results, the amount of PL, CL, AFM utilized examines the thick films, prove thermal annealing will reduce the stress of interfaces and density of defect effectively. And then regrowth in the experiment, change different growth parameters, utilize PL, CL, AFM, XRD amount to examine and analysis, and then find out optimum value, let re-grown of GaN thick films have better quality.