半导体应变超晶格结构与界面的X射线双晶衍射研究

INVESTIGATION OF THE SEMICONDUCTOR STRAINED SUPERLATTICE STRUCTURE AND INTERFACE BY X-RAY ROCKING-CURVE ANALYSIS

本文应用X射线在畸变晶体中的动力学衍射理论,分析了超晶格衍射峰强度分布的规律,计算了应变超晶格中界面变化,层厚波动对双晶摇摆曲线的影响,并初步探讨了超晶格衍射峰之间的小峰消失以及衍射峰宽化的原因,研究表明,衍射峰强度分布依赖于超晶格周期中层厚、成份及应变的综合效果,界面和层厚波动将对摇摆曲线产生一定影响,而晶格弯曲是使衍射峰宽化的主要原因。

The dynamical theory as developed by Takagi and Taupin for imperfect crystals has been applied to analyse the intensity distribution of the superlattice diffraction peaks, and to compute the rocking curves when the interface grading and the period thickness fluctuation are present. The reason why the interference fringes between the superlattice diffraction peaks disappear and the superlattice diffraction peaks broaden are discussed. It is clear that the intensity distribution of the superlattice diffraction peaks depends on the superlattice period thickness, the composition and strain in it. The interface gradient and the period thickness fluctuation may affect the double-crystal rocking curves. The main reason of the superlattice diffraction peak broadening is the bending of lattice plane.