Peking Univ, Sch Phys, Beijing 100871, Peoples R China
; Peking Univ, State Key Lab Artificial Microstruct & Mesoscop P, Beijing 100871, Peoples R China
; Peking Univ, Res Ctr Wide Band Semicond, Beijing 100871, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100049, Peoples R China
We investigate mosaic structure evolution of GaN films annealed for a long time at 800 degrees C grown on sapphire substrates by metalorganic chemical vapour deposition by high-resolution x-ray diffraction. The result show that residual stress in GaN films is relaxed by generating edge-type threading dislocations (TDs) instead of screw-type TDs. Compared to as-grown GaN films, the annealed ones have larger mean twist angles corresponding to higher density of edge-type TDs but smaller mean tilt angles corresponding to lower density of screw-type TDs films. Due to the increased edge-type TD density, the lateral coherence lengths of the annealed GaN films also decrease. The results obtained from chemical etching experiment and grazing-incidence x-ray diffraction (GIXRD) also support the proposed structure evolution.
Chen, ZT,Xu, K,Guo LP,et al. Mosaic structure evolution in GaN films with annealing time grown by metalorganic chemical vapour deposition[J]. CHINESE PHYSICS LETTERS,2006,23(5):1257-1260.
Chen, ZT.,Xu, K.,郭立平.,Guo, LP.,Yang, ZJ.,...&Zhang, GY.(2006).Mosaic structure evolution in GaN films with annealing time grown by metalorganic chemical vapour deposition.CHINESE PHYSICS LETTERS,23(5),1257-1260.
Chen, ZT,et al."Mosaic structure evolution in GaN films with annealing time grown by metalorganic chemical vapour deposition".CHINESE PHYSICS LETTERS 23.5(2006):1257-1260.