XRD Characterization Of GaAs-Based Hetero-Epitaxy Materials And SiC MESFET Structure Materials

X-ray double crystal diffraction (XRD) technology, characterized by its advantages such as non-destructive, high precision, and simple operation and so on, was widely used in modern semiconductor material analysis. Some important information including the integrity of crystallization, uniformity, thickness, composition, strain, defects, interfaces and so on, could be obtained by XRD.In the paper, GaAs-based multi-heterostructure-layers materials and SiC MESFET homoepitaxial materials were grown by MBE and CVD techniques, respectively. The structure parameters and interface perfection were studied by using X-ray Kinematics and RADS software. Specific details were as follows:1. The InGaAs/GaAs multi-quantum wells structure parameters had been calculated and simulated by using X-ray Kinematics and RADS software. Experimental results showed that the quantum wells material could achieve the precise control of thickness and composition by using double-speed growth and suspension growth technologies. The film thickness error of wells and barriers layers in ultra-thin films structure were only a few angstroms, and the percentage error of In composition was less than 1.9%. ECV experimental results also indicated that the percentage error of doping concentration was also less than 3.3% by using two Si sources in MBE system, and the two Si sources were set different temperatures to implement high doping and low doping, respectively.2. Dispersion effect caused by X-ray bandwidth between Ka1 and Ka2 in the double crystal X-ray diffractometer system was studied, and the calculation methods and formulas of the diffraction peak broadening width were derived from Bragg's law. Results analysis showed that the broadening width of diffraction peak was directly related to the difference size between samples and reference crystal diffraction surface.3. Analysis and discussion had been given to the relatively low diffraction intensity in 4H-SiC crystal and 4H-SiC MESFET homoepitaxy materials (004) surface. A detailed study also were carried out on the effect of the special double-atom-layer structure in X-ray diffracting process.