MicroRaman study of bulk inclusions in SiC crystals

The growth of defect-free SiC substrates is of primary importance for the development of devices based on this material, since defects such as micropipes and crystalline inclusions limit the performance of SiC-based devices. The analysis of these defects is crucial for the improvement of these crystals. MicroRaman spectroscopy provides structural and electronic information with micrometric spatial resolution. We present herein a microRaman study of different solid inclusions in 4H-SiC; the results are discussed in terms of the polytype structure, crystal orientation in relation to the matrix, and local electron concentration and mobility around the solid inclusions.