Investigation Of Molecular Dynamics Of Structural Defects In 4H-SiC Epitaxial Layers

4H-SiC is wide bandgap compound semiconductors suitable for high breakdown voltage, high power, and high frequency device applications. The major drawback is the effects of structural defects, which often limit the performance, yield, and reliability of the fabricated devices. This paper focuses on the defects in the 4H-SiC homoepitaxial layers. The reasons for the formation of the defects and the influence of the defects on the materials were mainly studied. So we try to understand the microscopic mechanism by molecular dynamics simulation methods,this is very meaningful.Firstly, structures of SiC crystal and their relationship with defects were introduced in details. Also, two kinds of defects in the SiC epitaxial materials, morphologic and structural defects, were presented. And the origin, properties and influence on devices were discussed. Besides, several ways of characterization of defects were introduced in the paper, such as atomic force microscope, photoluminescence, transmission electron microscope, X-ray diffraction and Raman scattering spectroscopy.Secondly, explained the dislocation theory, including the elastic field model of dislocations, the classification of dislocation and the dislocation force. The contents comprise the classification and principle of molecular dynamics, the methods of simulation, the related finite difference technique, the choice of initial and boundary conditions, with special emphasis on potential function and Parinello-Rahman method.Lastly, the structural defects in the 4H-SiC epitaxial materials were studied. And the dislocations, stacking faults , MPs and TSDs were studied in details. With simulating of molecular dynamic,The kink pair migration analysis have demonstrated that the symmetric reconstructions (SRs) are always more likely to migrate, in particular Si(g) core dislocations is always more mobile than the the other partials.