X-Ray Imaging and TEM Study of Micropipes Related to their Propagation through Porous SiC Layer/SiC Epilayer Interface

The understanding of micropipes in porous SiC has improved through x-ray synchrotron imaging. The use of phase sensitive radiography makes it possible to visualize micropipes in porous SiC substrates with high sensitivity and resolution. The micropipes have been observed as individuals and as plane or twisted dipoles. Some of individual micropipes were found to localize close to voids. High porosity associated with micropipes was revealed. The defect configurations provide clues on the mechanisms of micropipe sealing in porous SiC layers in the course of epitaxial overgrowth. The models are suggested to describe micropipe sealing.