Low-Power and Highly Reliable Multilevel Operation in ZrO2 1T1R RRAM

The Ti/ZrO2/Pt resistive memory devices with one transistor and one resistor (1T1R) architecture are successfully fabricated in this letter. The tested devices show low operation current (20 mu A), low switching voltage (set/reset, 0.8/-1 V), and reliable data retention for low-resistance state (LRS) with a 20-mu A set current at 80 degrees C (over ten years) via an excellent current limiter, namely, a metal-oxide-semiconductor field-effect transistor (MOSFET). In addition, multilevel storage characteristics are also demonstrated by modulating the amplitude of the MOSFET gate voltage. The various LRS levels obtained are possibly attributed to the formation of different numbers and sizes of conducting filaments consisting of oxygen vacancies caused by an external electric field. Moreover, reproducible resistive switching characteristics up to 2000 switching cycles are achieved in the same device. Our 1T1R ZrO2-based resistive switching access memory with low-power and highly reliable multilevel operation has high potential for practical applications.