Morphology and microstructure evolution of AlzGa(1-z)N epilayers grown on GaN/sapphire templates with AlN interlayers observed by transmission electron microscopy
Morphology and microstructure evolution of Al0.3Ga0.7N epilayers grown on GaN/sapphire templates with low-temperature (LT) AlN interlayers (ILs) by means of metal organic chemical vapor deposition have been investigated by transmission electron microscopy and atomic force microscopy. It is found that the IL improves the surface morphology,and suppresses edge-type threading dislocations (TDs). When the IL thickness is 20 nm,there is the lowest density of the edge-type TD with 8.7×108cm(-2). But the edge-type TD density increases somewhat as IL thickness increases to 40 nm. It is believed that two mechanisms determine the microstructure evolution of the AlxGa(1-x)N epilayers. One is the TDs suppression effect of LT-AlN ILs that ILs can provide an interface for edge-type TDs termination. Another is the TDs introduction effect of ILs that new edge-type TDs are produced. Due to the lattice mismatch between AlN,GaN and AlxGa(1-x)N,the strain in AlxGa(1-x)N epilayers is modified by inserting the AlN IL,and thus changes the formation of the edge-type TDs.
L.Lu J.Xu D.P.Yu B.Shen F.J.Xu S.Huang Z.L.Miao Z.X.Qin Z.J.Yang G.Y.Zhang X.P.Zhang
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics,School of Physics,Peking Un Electron Microscope Laboratory,Peking University,Beijing 100871,China
国际会议
9th International Conference on Solid-State and Integrated-Circuit Technology(第9届固态和集成电路国际会议)
北京
英文
722-725
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）