Implant-isolated SAW storage correlator

The development of surface acoustic wave (SAW) convolvers and correlators is reviewed. This is followed by the introduction of a new type of monolithic metal-zinc oxide-silicon dioxide-silicon storage correlator. Fabrication and operation of the implant isolated storage correlator, which relies on ion implantation for confinement of storage regions, is detailed. A capacitance-time measurement procedure for evaluation of the charge storage capability of the device is described, and correlation output information is used to estimate the effective recombination rate of the inversion layer charges. Finally, operational characteristics are examined and the new bias stable device is shown to exhibit a 3-dB storage time in excess of 0.5 s. The cited storage time exceeds reported storage times of other structures fabricated in the ZnO-SiO2-Si layered medium configuration.