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采用X射线多功能四圆衍射仪测绘出GaN/GaAs(0 0 1 )外延层中六角相的{0 0 0 2 }和 {1 0 1 0 }极图 ,结果表明外延层中六角相与立方相之间的取向关系为 :{0 0 0 1 }∥ {1 1 1 },〈1 0 1 0〉∥〈1 1 2〉 .构建了相应的结构模型 ,并对 {0 0 0 2 }和 {1 0 1 0 }极图进行了模拟 .六角相以该取向关系存在于立方相GaN外延层中时 ,两相界面处具有相应于六角相和立方相的层错结构 .分析立方相GaN外延层中形成六角相所导致的晶格畸变和能量变化可知 ,造成六角相分布特征的主要因素是平行于〈0 0 0 1〉方向的两相界面处原子成键紊乱 .六角相按照该取向关系 ,从低温缓冲层内部或缓冲层与外延层界面处萌生 ,并以片状贯穿至外延层表面的分布特征所引起的外延层能量增加值最小
The hexagonal {0 0 0 2} and {1 0 1 0} pole figures of GaN / GaAs (0 0 1) epitaxial layers were measured by X-ray multifunctional four-circle diffractometer. The results show that the hexagonal and cubic The orientation relationship between phases is: {0 0 0 1} ∥ {1 1 1}, <1 0 1 0> ∥ <1 1 2>. The corresponding structural model is constructed and the relationship between {0 0 0 2} and {1 0 1 0} pole figure was simulated.When the hexagonal phase was present in the cubic GaN epitaxial layer in this orientation relationship, the two-phase interface had a layered fault structure corresponding to the hexagonal and cubic phases. It can be seen that the main factor causing the distribution of hexagonal phase is the disorder of atom bond at the interface of two phases parallel to <0 0 0 1> direction. According to the orientation relationship of hexagonal phase , The epitaxial layer energy increment caused by the distribution characteristics of the inner part of the buffer layer or the interface between the buffer layer and the epitaxial layer and the distribution characteristic of the sheet through the surface of the epitaxial layer is the smallest