SBIR Phase I: Resonance Ultrasonic Vibrations for Defect Characterization in Solar Silicon Wafers

This Small Business Innovative Research (SBIR) Phase I research project addresses fundamentals of the innovative experimental methodology for quick and accurate assessment of mechanical defects in solar-grade full-size (up to 210 mm) silicon (Si) wafers. The objective is to justify a commercial prototype of the Resonance Ultrasonic Vibrations (RUV) system which ultimately will be used as a real-time in-line process control tool for identification and rejection from a solar cell production line of mechanically unstable, i.e. fragile wafers due to periphery cracks and high level of residual stress. The broader impact of the program will be in the commercialization of the RUV system to address critical needs of the photovoltaic (PV) industry. The world-wide PV market exhibits a steady yearly up to 40% growth rate in recent years. There is potential for applying this approach to other technologies, such as stress monitoring in Silicon-on isolator wafers and SiGe epitaxial layers in high-speed electronics and adhesion quality assessment in thin polycrystalline Si films on glass for flat panel displays.