采用铟束流保护下的调制中断生长技术改善(0001)GaN表面形貌

使用分子束外延方法,采用In束流保护下的调制中断生长技术,在(0001)蓝宝石衬底上生长GaN薄膜.利用反射式高能电子衍射(RHEED)对生长进行实时监控,并用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)法对GaN外延薄膜的表面形貌和晶体质量进行分析.实验结果表明:采用该技术生长的Ga极性GaN外延薄膜中的晶体表面残留Ga滴密度大大降低,GaN外延薄膜的表面形貌得到改善,其均方根粗糙度(RMS)由3nm降低为0.6nm,同时XRD双晶摇摆曲线测试的结果表明,GaN外延层的晶格质量也得到改善.

Improvement of Surface Morphology of RF MBE Grown (0001) GaN via In-Protected Growth Interruption Modulation

GaN layers have been deposited on (0001) sapphire substrates using radio frequency molecular beam epitaxy by In-protected growth interruption modulation.The growth process is monitored by in-situ reflection high-energy electron diffraction.The morphological and structural properties of GaN films are investigated by scanning electron microscopy,atomic force microscopy,and X-ray diffraction (XRD).The results indicate that the density of gallium droplets on the GaN surface is greatly reduced,and the morphology of the GaN films is improved.The RMS is reduced to 0.6nm,while it is 3nm without using this technique.Furthermore,the XRD rocking curves show that the structural quality of the films is superior to that of GaN films formed without using this technique.