Room Temperature Photoluminescence Characterization of Interface Quality of SiN/SiO2/Si Prepared under Various Deposition Techniques and Conditions

Abstract

Room temperature photoluminescence (RTPL) spectroscopy was examined as an in-line monitoring technique for characterizing the interface of ultra-thin (~7.2 nm) stacked dielectric films (SiN/SiO2) on 300 mm Si wafers. To investigate the effect of the stacked dielectric films on electronic properties at the interface, RTPL signals were measured under various excitation wavelengths with different probing depths. Changes of interface quality of the stacked dielectric films and the Si wafer were investigated using various specimens prepared by different deposition techniques and conditions. The overall interface quality of the SiN/SiO2/Si specimens was found to be very dependent on the SiN deposition technique and process conditions. N-rich SiN films resulted in very intense RTPL signals. As the stoichiometry of SiN films change from N-rich to Si-rich conditions, the RTPL signal becomes weaker, indicating the change of electronic properties at the SiN/SiO2/Si interface. Within-wafer and wafer-to-wafer variations of the SiN/SiO2/Si interface quality were successfully characterized by RTPL spectroscopy under various excitation wavelengths.