Fast Defect Mapping at the SiO₂/ SiC Interface Using Confocal Photoluminescence

Abstract

Electrically active defects at the SiO2/SiC interface can have detrimental effects on the device performance of SiC MOSFETs. Capacitance-or conductance-based analysis techniques are commonly used to extract the density of interface defects, despite having the disadvantage of requiring dedicated test structures for the analysis. Here, we discuss confocal sub-bandgap photoluminescence (PL) microscopy as a fast and reliable alternative to conventional electrical characterization techniques. For this purpose, the quality of the SiO2/SiC interface after post-oxidation annealing in N2O is studied both by confocal imaging as well as by the high-low and C-Ψ capacitance technique. We find excellent agreement between the optical and electrical analysis and observe a significant increase of the interface defect density for annealing temperatures below 1050 °C. Keywords: interface defect density, photoluminescence, capacitance-voltage