ZnTe/GaSb结构的X射线三轴晶散射和晶体截断杆研究

用X射线三轴晶散射和晶体截断杆扫描研究了不同工艺条件下分子束外延生长的ZnTe/GaSb结构．X射线晶体截断扫描显示，从衬底表面清洁温度到生长温度退火过程中采用Zn气氛的样品具有清晰的干涉条纹，而在Te气氛下退火则晶体截断扫描没有干涉条纹．在倒易点004，115附近X射线散射的二维强度分布图显示，两种条件下生长样品的晶格失配应力都没有弛豫．二维等强度分布图和沿［110］方向的扫描，都显示在Te气氛下生长的膜具有较强的漫散射，并且分布较宽．这种漫散射来源于界面相Ga₂Te_{3< 关键词：}

INVESTIGATION OF THE STRUCTURES OF ZnTe/GaSb BY X-RAY TRIPLE-AXIS SCATTERING AND CRYSTAL TRUNCATION ROD

The structures of ZnTe/GaSb, grown by molecular beam epitaxy under different conditions, were investigated by X-ray triple-axis scattering and crystal truncation rod. The sample annealed under Zn flux from surface cleaning temperature to growth temperature had clear interference fringes in the crystal truncation rod scan profile, while the sample annealed under Te flux shows no interference fringes in the crystal truncation rod. Reciprocal space mapping around the symmetrical diffraction reciprocal point 004 and asymmetrical diffraction point 115 showed that the ZnTe epilayers were fully strained to the substrate. Both two-dimensional reciprocal space mapping and transverse scan along direction showed that the sample annealed under Te flux had strong and broad diffuse scattering in this direction. This was attributed to the Ga₂Ｔｅ₃ formation at the interface. This interfacial phase would enhance the diffuse scattering, blur the interference fringes and roughen the surface and interface. The epilayer thickness was accurately determined to be (210±1)nm by theoretical calculation of the experimental profiles. The surface roughness of the sample annealed under Zn flux, (2.2±0.2)nm, was smaller that of the sample annealed under Te flux, (3.7±0.3)nm.The lateral correlation lengths of the samples annealed under Zn flux and Te flux are (420±10)nm and (30±5)nm,respectively.