The thermal stability of one-transistor ferroelectric memory with Pt-Pb5Ge3O11-Ir-poly-SiO2-Si gate stack

The thermal stability of one-transistor ferroelectric nonvolatile memory devices with a gate stack of Pt-Pb₅Ge₃O₁₁-Ir-Poly-SiO₂-Si was characterized in the temperature range of -10°C to 150°C. The memory windows decrease when the temperatures are higher than 60°C. The drain currents (I_D) after programming to on state decrease with increasing temperature. The drain currents (I_D) after programming to off state increase with increasing temperature. The ratio of drain current (I_D) at on state to that at off state drops from 7.5 orders of magnitude to 3.5 orders of magnitude when the temperature increases from room temperature to 150°C. On the other hand, the memory window and the ratio of I_D(on)/I_D(off) of the one-transistor memory device displays practically no change when the temperature is reduced from room temperature to -10°C. One-transistor (1T) memory devices also show excellent thermal imprint properties. Retention properties of 1T memory devices degrade with increasing temperature over 60°C.