Characterization of Threading Screw Dislocations of Burgers Vectors with A-Components in 4H-SiC

We characterized threading screw dislocations to investigate the influence on device performance. The Burgers vectors of the threading screw dislocations (a total of 28dislocations) in 4H-SiC were determined by large-angle convergent-beam electron diffraction. A new type of TSD, b=c+2a dislocation was identified. And all of the four types of TSD predicted were identified. The frequency of their occurrence observed experimentally is in good agreement with theoretical prediction. In addition, we investigated relations of Burgers vector and the dislocation line direction. It has been confirmed that the Burgers vector of TSD does not necessarily coincide with the direction of dislocation lines. Looking ahead, we need to investigate how the angle between Burgers vector and dislocation line influence device performance.