The populations and propagation behaviors of pure and mixed threading screw dislocations (TSDs) in physical vapor transport (PVT) grown 4H-SiC crystals were investigated using X-ray topography. The X-ray topography studies revealed that mixed TSDs, which have a Burgers vector component within the basal plane in addition to the c -component, were dominant in PVT-grown 4H-SiC crystals, even though they have a higher energy contained in the elastic field around them compared to pure TSDs. The studies also revealed that mixed TSDs tended to propagate in a specific direction inclined from the c -axis, whereas pure TSDs were often converted into helical dislocations during the PVT growth. Based on these results, we discussed the nature and propagation behavior of pure and mixed TSDs in PVT-grown 4H-SiC crystals and suggested an importance of the interaction between TSDs and point defects during PVT growth of 4H-SiC.

中文翻译：

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利用X射线形貌研究纯的和混合螺纹位错在物理气相传输生长的4H-SiC晶体中的种群和传播行为

利用X射线形貌研究了纯螺旋和混合螺纹位错（TSD）在物理气相传输（PVT）生长的4H-SiC晶体中的种群和传播行为。X射线形貌研究表明，混合的TSD在PVT生长的4H-SiC晶体中占主导地位，除了c成分外，它在基面上还具有Burgers矢量成分，即使它们具有较高的能量。与纯TSD相比，它们周围的弹性场更大。研究还显示，混合的TSD倾向于在从c轴倾斜的特定方向上传播，而纯的TSD在PVT生长期间通常会转化为螺旋位错。根据这些结果，