Resistive switching characteristics of integrated polycrystalline hafnium oxide based one transistor and one resistor devices fabricated by atomic vapor deposition methods

In this work, the bipolar resistive switching (RS) characteristics of polycrystalline hafnium oxide are studied in embedded 1 transistor-1 resistor (1T1R) resistive random access memory (RRAM) devices. The HfO2 films with varied thickness from 15 to 25 nm were grown by the atomic vapor deposition method at 400 °C. The HfO2 films are polycrystalline, as evaluated by applying atomic force microscopy and x-ray diffraction. In addition, current–voltage characteristics of the 1T1R devices were investigated. The forming voltages of 15 nm thick HfO2 films are about 4 V and increase gradually with increasing film thickness. A reproducible resistance switching behavior was observed with a high resistance ratio of ∼20 during DC cycling of 100 times. The observed SET and RESET voltages are about 1.2 and 1.6 V, respectively, indicating that the 1T1R RRAM device can be operated below 2 V. The current–voltage characteristics are discussed in the frame of the quantum point contact model.