低位错密度的XRD无损表征研究

The Study of XRD Nondestructive Characterization at Low Dislocation Density

当半导体材料中位错密度大于107cm-2,难以用传统的腐蚀法进行测量时,可以利用高分辨X射线衍射(XRD)峰的半高宽估算材料中位错密度。该文利用该方法研究了位错密度小于107cm-2时是否适用的问题。结果表明,材料中位错密度较低(5.3×105cm-2)时,利用XRD测得的位错密度值与实际值存在3个数量级的偏差。分析认为,当晶体中位错密度较低时,参与衍射的晶面就越多,衍射峰就越窄,当位错加宽值与仪器精度接近时,就会产生较大偏差。因此在低密度位错时,利用XRD方法测量材料中位错密度时容易产生较大偏差。

It is difficult to measure by conventional etching method when the dislocation density of the semiconductor material is greater than the 107cm-2. Dislocation density can be estimate utilized in high resolution X--ray diffraction （XRD） peak half--width in this case. In this article, whether to apply using this method in less than 107cm-2 of the dislocation density is studied.The results show there has the three orders of magnitude of the deviation between measured values and actual values at. 5.3X105cm-2.Analysts believe that when the crystal dislocation density is low, the diffraction peak is more narrower. When the value of the dislocation widening approach to instrument accuracy, it will have a greater bias. Therefore, it will prone to large deviation when measured by XRD at dislocation density.