Semiconductor-ferroelectric nonvolatile memory using anomalous high photovoltages in ferroelectric ceramics

A small ferroelectric ceramic element is used with an insulating gate transistor and two diodes as an electrically addressed, nonvolatile memory device which is read out nondestructively. The device uses the anomalous photovoltaic effect in ferroelectric ceramics, an effect in which the polarity and magnitude of photovoltages depend on the direction and magnitude of remanent polarization. Experimental results give memory characteristics. The device could be programmed with pulses as short as 200 ns. There is long-time retention of stored data.