Memory properties of a ferroelectric gate field-effect transistor with an adjoining metal–ferroelectric–metal assistance cell

We prepared a ferroelectric gate field-effect transistor (FET) memory that consists of a normal metal–ferroelectric–metal-insulator–Si FET and an adjoining metal–ferroelectric–metal auxiliary cell. Due to this cell, the FET exhibited excellent nonvolatile memory properties of low-voltage operation and a long period of retention. After writing-voltage application of ±4 V, the drain current ratio between “ON” and “OFF” states was as large as six orders of magnitude and the memory window (difference in threshold voltage) was 3 V. Even ${10}^4 \mathrm{s}$ after writing, the ON state drain current could be distinguished as being three orders different from the OFF state current. The ferroelectric FET with the auxiliary cell that demonstrated good nonvolatile properties has potential for application in high-density nonvolatile memories.