Nondestructive Readout of Ferroelectric-Gate Field-Effect Transistor Memory With an Intermediate Electrode by Using an Improved Operation Method

Susumu Horita,Bui Nguyen Quoc Trinh

doi:10.1109/ted.2008.2003329

Abstract

We investigated the reading and writing of ferroelectric-gate field-effect transistor memory with an intermediate electrode (IF-FET) to achieve perfect nondestructive readouts. In the previous operation method, although the difference in output voltage Delta V O between positive ( P r + ) and negative ( P r - ) remanent polarization memory states was adequate for the first reading time, the nondestructive readout for the P r - state was seriously degraded due to the generation of nonreturning domains. In order to solve this issue, a P r 0 memory state was used instead of the previous P r - memory state. The P r 0 state was induced by applying a pulse combined with a positive voltage ( V W + ) and a negative voltage ( V W - ). V W + was to reset the previously written memory states, and V W - was to control the amount of remanent polarization. In addition, in order to extinguish perfectly the nonreturning domains, a negative voltage V R - was applied for data reading, following a positive voltage V R + , where V R + was determined for clear decoding. The appropriate heights of the writing and reading voltages were determined individually from the viewpoint of good nondestructive readout and large Delta V O . As a result, it was verified experimentally that the reading endurance reached more than 10 8 cycles and that the retention time of IF-FET at 150 deg C was possible to exceed ten years.

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