A method to determine superscrew dislocation structure in silicon carbide

A method to determine the magnitude and the sign of Burgers vectors of superscrew dislocations in silicon carbide (SiC) single crystal has been developed. The investigated superscrew dislocations include both elementary screw dislocations and micropipes. Quantitative investigations showed that, in high-quality commercial 6H SiC wafers, most micropipes are 4c or larger, some of 3c-7c dislocations are closed-core, and none of 2c dislocations are open-core. The magnitude of the Burgers vector is statistically proportional to the diameters of micropipes, which follows Frank's prediction. The surface energy of the micropipes in 6H SiC is estimated to be 2.0 J m−2.