Nonlinear resonance ultrasonic vibrations in Czochralski-silicon wafers

S. Ostapenko, I. Tarasov
2000 Applied Physics Letters  
A resonance effect of generation of subharmonic acoustic vibrations is observed in as-grown, oxidized, and epitaxial silicon wafers. Ultrasonic vibrations were generated into a standard 200 mm Czochralski-silicon ͑Cz-Si͒ wafer using a circular ultrasound transducer with major frequency of the radial vibrations at about 26 kHz. By tuning frequency ͑f͒ of the transducer within a resonance curve, we observed a generation of intense f /2 subharmonic acoustic mode assigned as a "whistle." The
more » ... histle." The whistle mode has a threshold amplitude behavior and narrow frequency band. The whistle is attributed to a nonlinear acoustic vibration of a silicon plate. It is demonstrated that characteristics of the whistle mode are sensitive to internal stress and can be used for quality control and in-line diagnostics of oxidized and epitaxial Cz-Si wafers.
doi:10.1063/1.126301 fatcat:irqzwoj64ve6lox7enfitthazq