MOSFET surface wave detectors for high frequency signal processing

The piezoresistance effect in Si-MOSFET structures is used for the detection of Rayleigh surface waves launched on a silicon substrate. The semiconductor devices are MOSFET N and P-channel inversion layers, the channel length is along the direction of the wave propagation and many elementary detectors have been disposed along the propagation path in order to realize tapped delay lines. Theoretical and experimental results are given for the conversion efficiency, bandwidth, sensitivity and dynamic range for a single N or P channel device. Results are presented also for an array of detectors operating as a variable delay line and as a correlator for a 50 MHz bit rate waveform.