Nonvolatile Charge-Trap Memory Transistors With Top-Gate Structure Using In-Ga-Zn-O Active Channel and ZnO Charge-Trap Layer

We proposed a charge-trap-type memory transistor with a top-gate structure composed of Al2O3 blocking/ZnO charge-trap/IGZO active/Al2O3 tunneling layer. The memory ON/OFF ratio higher than six-orders-of magnitude was obtained after the programming when the width and amplitude of program pulses were 100 ms and +/- 20 V, respectively. Excellent endurance was successfully confirmed under the repetitive programming with 10(4) cycles. The memory ON/OFF ratio higher than 10(3) was guaranteed even after the lapse of 10(4) s. Interestingly, the retention properties were affected by the bias conditions for read-out operations.