湿法化学腐蚀法估算GaN外延层中位错密度

Evaluation of Dislocation Densities in GaN Epilayers by Wet Chemical Etching

研究了采用熔融NaOH对MOCVD生长的GaN外延层的湿法腐蚀结果,结合原子力显微镜表征其腐蚀坑形貌及腐蚀坑密度,得出了优化的腐蚀条件。通过与熔融KOH腐蚀结果对比分析发现,熔融NaOH腐蚀速率平缓,表面更平整,腐蚀坑更规则且密度更大。结合两种腐蚀结果,可以初步得出,熔融NaOH对GaN中刃型分量位错敏感,而熔融KOH对螺型分量位错更敏感,两种腐蚀剂相结合能够更完整地揭示GaN内部位错。

Wet chemical etching using molten NaOH on GaN grown by MOCVD was studied. Optimized etching parameters were got by studying on the morphology and density of etch pits with AFM. Compared with the results in molten KOH, the etching surface and etching pits are more regular and the etching pits density is higher than that in molten NaOH. A primary conclusion is proposed that molten NaOH could reveal the dislocations including edge component of the Burgers vector, and molten KOH is more sensitive for the dislocations including screw component of the Burgers vector.