用卢瑟福背散射/沟道技术及高分辨X射线衍射技术分析不同Al和In含量的AlInGaN薄膜的应变

Strain in Al I[WTFZ]nGaN thin films caused by different contents of Al and In studied by Rutherford backscattering/channeling and high resolution x-ray diffraction

利用卢瑟福背散射/沟道技术对在蓝宝石衬底上用金属有机化学气相沉积方法生长的有GaN缓冲层(>2μm)的一系列不同Al和In含量的AlInGaN薄膜进行组分及结晶品质的测量;并结合高分辨X射线衍射技术,通过对AlInGaN的对称(0002)面,及非对称(1015)面的θ—2θ扫描及倒空间扫描,可以精确测定AlInGaN外延层的晶格常数及水平和垂直方向的应变.实验结果表明AlInGaN薄膜中不同含量Al和In对其应变有较大的影响,结合Vegard定理,对这一现象给出了理论的解释.

A series of AlInGaN films with different contents of Al and In were grown by metal-organic chemical vapor deposition on sapphire with GaN （ 〉 2 um） intermediate layer. Rutherford backscattering/channeling was used to measure the compositions and the crystal quality of the AlInGaN films. Combining with the high resolution x-ray diffraction, the lattice constants and the strain in perpendicular and the parallel directions of the AIInGaN epilayer can be determined accurately by the θ-2θ scan of （0002） and （10^-15） reflections and the reciprocal-space x-ray mapping. We find that different contents of In and Al can effect the strain in the quaternary AIInGaN films obviously, and with the help of Vegard＇ s law we give an explanation for this phenomenon.