XRD法计算4H-SiC外延单晶中的位错密度

Calculation of Dislocation Destiny Using X-Ray Diffraction for 4H-SiC Homoepitaxial Layers

对用X射线衍射法计算4H-SiC外延中的位错密度方法进行了理论和实验研究。材料中的位错密度大于106cm-2会给材料位错密度的测试会带来一定的困难。首先从理论上分析了位错密度对X射线衍射结果的影响,得出位错密度和峰宽FWHM展宽的关系。然后对4H-SiC样品进行了X射线三轴晶ω-2θ测试,采用不同晶面衍射峰,计算出样品的位错密度。分析了外延中位错产生的原因,并提出了相应的解决办法。

A theoretical and experimental study on calculating dislocation destiny for 4H-SiC homoepitaxial layers has been car ried out. There is some difficulty in measuring dislocation density if it is more than 106 · cm^- 2. In the paper, a theoretical analysis is made about the effects of dislocation density on the results of X-ray diffraction, and the relationship of dislocation density and FWHM spread is obtained. Then the X-ray diffraction curves of 4H-SiC in wr2θ with two different crystal faces are presented from which the density of dislocation is calculated. According to the result, the cause of dislocation origin is analyzed and the methods of decreasing dislocation density are proposed.