Distribution of Secondary Defects and Electrical Activation after Annealing of Al-Implanted SiC

We investigated the relationship between secondary defects and electrical characteristics in the activation annealing (1600 °C-1800 °C) of 4H-SiC after Al implantation (3 × 1017 cm-3-3 × 1019 cm-3). X-ray topography revealed that the dislocation density did not increase after implantation and annealing. Scanning transmission electron microscopy (STEM) images revealed black spots that aggregate with increase in Al dose. The results of energy dispersive X-ray spectroscopy analysis suggested that these black spots are due to the strain of secondary defects. The I-V characteristics at reverse bias of a pin diode fabricated with Al implantation show that secondary defects shown as black spots in the STEM images do not affect the electrical characteristics under the implantation and annealing conditions used in this experiment.