| 摘要 |
A dynamic random access memory having a non-volatile back-up storage capability including a latent image capability, and method of operating the memory. Each memory cell is composed of a dynamic portion and a non-volatile portion connected to the dynamic portion. The non-volatile portion is formed of a dual gate FET, one gate of which is a floating gate. A segment of DEIS (Dual Electron Injection Structure) material is provided to control the charge of the floating gate. A capacitor couples the floating gate to the source of the dual gate FET and to the data node of the cell. The second gate of the dual gate FET can be grounded to turn off the channel of the dual gate FET independent of the charge on the floating gate during normal dynamic memory operations. To perform a non-volatile storing operation, the voltage applied to the DEIS material opposite the floating gate is taken first positive and then negative. During the positive portion of the cycle, if the data at the data node is a data 0, a positive charge is stored on the floating gate, while if the data at the data node is a data 0, a positive charge is stored on the floating gate during the negative portion of the cycle. To restore the data, a data 1 is written at the data node and the second gate of the dual gate FET transistor is pulsed to thereby allow the charge stored on the floating gate to control the conductivity of the channel of the dual gate FET. If a positive charge is stored on the floating gate, the channel conducts and discharges the data node, while if a negative charge is stored on the floating gate, the channel remains non-conductive and the charge at the data node is retained. |
