Relationship between Infrared Photoluminescence and Resistivity in Semi-Insulating 6H-SiC

摘要

A combination of room-temperature photoluminescence (PL)mapping,low-temperature PL spectroscopy,and resistivity mapping was applied to establish the origin of resistivity variations in different types of semi-insulating (SI)6H-SiC substrates.Direct correlation between the native-defect PL and resistivity was found in undoped (V-free)SI samples.The regions with high PL intensity also showed high resistivity,indicating that native point defects are associated with the compensation mechanism in those substrates and its nonhomogeneity.A more complex correlation was established for the vana-dium-doped samples.In these samples,V-related PL and native point defect-related PL were both present at room temperature.While there was no clear correlation between the resistivity maps and the maps of PL intensity meas-ured at either of the two peaks separately,the resistivity was in good corre-lation with the total PL signal consisting of both vanadium and intrinsic defect contributions.The resistivity of those wafers was apparently due to the con-tribution of both V-related and native point defect-related deep levels.