Dislocations in 4H-SiC epilayers

Abstract

Properties and behavior of dislocations in 4H-SiC are presented based on classical theory of dislocations. 1) A new symbolwhich is an extension of the famous Frank symbol is introduced to explain complex stacking sequence in SiC polytypes. 2) A basal plane dislocation (BPD) is dissociated into two Shockley partials. Polarity of BPD is described. 3) Principles to assign Burgers vectors and polarity to the individual Shockley partials are derived. 4) Threading screw dislocations (TSD) can be dissociated into four partials, thereby reducing the total energy considerably. 5) Deviation of threading dislocations (TD) from the exact [0001] orientation is reasoned from the viewpoint of energy consideration. 6) Transition from BPD to threading edge dislocations (TED) is explained by taking into account effects of the crystal surface. All of behavior can be explained quite well in terms of classical theory of dislocations.