Micro-Raman Characterization of 4H-SiC Stacking Faults

Abstract

Micro-Raman characterization has been used as alternative technique to the photoluminescence in order to detect and study 4H-SiC stacking faults. The alteration of the crystalline stacking sequence perturbs the phonon-plasmon coupling which acts between the crystalline phonon modes and the electronic plasma, due to the doping element (N). The shape and the symmetry of the Longitudinal optical Raman mode is strongly correlated to the doping level of the material thus, through the monitoring of the Raman mode, the spatial morphology of the defect can be completely recovered and compared to the results provided by photoluminescence technique. The results show that such a technique allows a very fast inspection on large wafer, because it is totally independent of the stacking fault photoluminescence signals, which cover a large energy range, up to 0.7 eV.