Visualization of Si Surface and Interface Quality by Non-Contact Optical Characterization Techniques

Si lattice stress at or near the surface, and overall quality of the Si surface and interface were characterized using multiwavelength, high resolution Raman and photoluminescence (PL) spectroscopy. Depth profiling of Si lattice stress and electrically active defects/traps, at or near the Si surface and interface, was done using ultraviolet (UV) to infrared (IR) light sources, with different probing depths. Significant variations in Si lattice stress, Si bond lengths and electrically active defects/traps were found from Si wafers undergoing various process steps. Visualization of Si surface and interface quality was done on Si wafers following various device fabrication steps.