Direct transduction method for measuring the ultrasonic attenuation in Si(111) in the frequency range 100Â MHz-1Â GHz

A direct ultrasonic transduction method was investigated as a function of frequency in order to evaluate the ultrasonic attenuation in doped n-type Si(111) by using a setup where an incorporated small spring acts as an adjustable coil. Measurements were performed in the frequency range from 100 MHz to 1 GHz using an AlN transducer produced directly on the Si sample. A vector network analyzer (VNA) was used to record the acoustic reflections. Dependence of the generated wave central frequency on transducer thickness, active area and circuit impedance was examined. One-dimensional (1D) simulations using an equivalent electrical circuit were carried out to validate the VNA measurements. An overall agreement was observed. The wave attenuation in the highly doped n-type Si(111) was found to have a quadratic dependance on the frequency.