High Device Yield of Resistive Switching Characteristics in Oxygen-Annealed SrZrO3 Memory Devices

Abstract

This paper reports the effects of rapid thermal annealing (RTA) on resistive switching (RS) characteristics and mechanisms of SrZrO3 (SZO)-based memory devices. SZO thin films were deposited on LaNiO3 (LNO) (100)/Pt/Ti/SiO2/Si using radio-frequency magnetron sputtering and were followed by an RTA process in N-2, Ar, and O-2 ambients, respectively, at various temperatures for improving RS performance. Experimental results indicate that an SZO device annealed in O-2 at 600 degrees C (O-2-600) exhibits stable RS properties and has a high device yield (similar to 90%), a reliable retention characteristic (up to 1 x 10(6) s at 100 degrees C), and steady nondestructive readout properties (over 1.4 x 10(4) s at 100 degrees C). However, by increasing RTA temperature to more than 700 degrees C, random formation of LNO (110) precipitates on the bottom surface of SZO grains might shorten the effective thickness of the SZO thin films. Furthermore, a strong electric field possibly occurs at the region between Al top electrodes and low-resistivity LNO precipitates. It is speculated that an RS phenomenon, which occurs within SZO grains instead of on grain boundaries, easily leads to RS failure, further resulting in severe degradation of device yield in the O-2-700 and O-2-800 devices. When compared with other devices, O-2-600 SZO memory devices exhibit highly reliable RS characteristics.