Room Temperature Photoluminescence Characterization of Silicon Wafers for In-Line Monitoring Applications

Overall quality of the Si surface and dielectric/Si interface including cleanliness, passivation and surface recombination characteristics were characterized using room temperature photoluminescence (PL) spectroscopy. The spectral resolution and spatial resolution of PL spectroscopy are approximately 1 nm and tens of microns. To understand the depth distribution of electrically active defects/traps, at or near the Si surface and the dielectric/Si interface, different excitation wavelengths (with different probing depths) were used as the excitation light source. Significant variations in electrically active defects, traps, and contaminants, at or near the surface, and the dielectric/Si interface were found from Si with native oxide. Multiwavelength PL spectroscopy was also able to reveal electrically active defects and characteristics induced by the cleaning process and dielectric film deposition process steps. Multiwavelength PL spectroscopy is a promising and readily available technique for in-line monitoring of Si wafers at various stages of process.