Appearance of local strain fields and high electrical conductivity of macro-defects in P+-implanted 4H-SiC

Abstract

We investigated the implantation-temperature-dependence of defect structures of P+-implanted 4H-SiC using synchrotron white-beam x-ray topography, which revealed hitherto unknown defect images in SiC implanted at 300 and 500 °C, though they were not observed in SiC implanted at 30 and 150 °C. These defects corresponded to small bump and saucer-pit defects, called generally "macro-defects," which were originally located on the initial surface of the SiC epilayer. After subsequent annealing at 1600 °C, the x-ray topographic images of the bump defects were similar to those of threading screw dislocations, but the images of the saucer-pit defects were not visible. Scanning probe microscopy (SPM) revealed that the bump defects had locally higher electrical conductivity (above 70 nA) than the surrounding SiC matrix both after implantation at 500 °C and after annealing at 1600 °C. Lower electrical conductivity (below 1 nA) was observed for the saucer-pit defects. The formation of the specific strain fields around the macro-defects and the appearance of implantation-driven high electrical conductivity at the bump defects are discussed on the basis of the SPM observation and electron probe microanalysis. © 2013 © 2013 Author(s).