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通过分别改变电感耦合等离子体(ICP)刻蚀过程中的ICP功率和DC偏压,对ICP刻蚀GaN材料的工艺条件和损伤情况进行了系统的研究。刻蚀后表面的损伤和形貌通过扫描电子显微镜(SEM)、原子力显微镜(AFM)、电子能谱(EDS)、荧光光谱(PL)等技术进行表征和分析。实验结果表明,刻蚀速率随ICP功率和DC偏压的增加而增加;刻蚀损伤与DC偏压成正比,而与ICP功率的关系较为复杂。实验中观测到刻蚀后GaN样品的荧光光谱带边发射峰和黄带发射峰的强度均有明显下降,这意味着刻蚀产生的缺陷中存在非辐射复合中心,并且该非辐射复合中心的密度与DC偏压成正比。为了兼顾高刻蚀速率和低刻蚀损伤,建议使用高ICP功率(>450 W)和低DC偏压(<300 V)进行ICP刻蚀。
The process conditions and the damage of GaN by ICP were studied systematically by changing the ICP power and DC bias in the process of inductively coupled plasma (ICP) etching respectively. The surface damage and morphology after etching were characterized and analyzed by scanning electron microscopy (SEM), atomic force microscope (AFM), electron spectroscopy (EDS) and fluorescence spectroscopy (PL). The experimental results show that the etching rate increases with the increase of ICP power and DC bias voltage. The damage of etching is proportional to the DC bias and the relationship with ICP power is more complicated. It is observed that the fluorescence emission band edge and the emission peak intensity of yellow band in GaN samples after the etching are obviously decreased, which means that there are non-radiative recombination centers in the defect caused by etching, and the non-radiative recombination center The density is proportional to the DC bias voltage. For both high etch rates and low etch damage, ICP etching with high ICP power (> 450 W) and low DC bias (<300 V) is recommended.