Convolution in a Pulse Biased ZnO-SiO2-Si Saw Device

A monolithic SAW device consisting of an rf sputtered ZnO film on a thermally oxidized silicon substrate has been shown to be useful for several signal processing and optical image scanning applications. The device efficiency and sensitivity can be varied greatly by employing any of several biasing techniques, both dc and pulsed. We report new effects related to a pulse biasing method which exploits surface states at the SiO2-Si interface. The increased optical sensitivity obtained by this technique makes the device an attractive optical scanner and optically programmed adaptive convolver.