Photoluminescence Analysis of Individual Partial Dislocations in 4H-SiC Epilayers

Configurations of the basal plane dislocations in 4H-SiC epitaxial layers are classified into two types, having typical combinations of ‘straight Si-core and straight C-core’ and ‘straight Si-core and curved C-core’ partial dislocations. The core species are determined by the photoluminescence images and observation of the moving Si-core partial dislocations by ultra-violet light illumination. Each partial dislocation was analyzed by photoluminescence spectroscopy. As the results, C-core partial dislocations have been found to have different peak wavelengths depending on the excitation power of the illumination. Also from the detailed analysis of individual partial dislocations, the curved C-core partial dislocations have been found to have different characters which may be originated from the mixture of different types of dislocations. It has been suggested that this model is possibly described by continuous connection of 30o and 90o dislocations which have different configurations of dangling bonds. The difference in photoluminescence peak wavelength might be explained by the structural difference.