High-Performance Multilevel Resistive Switching Gadolinium Oxide Memristors With Hydrogen Plasma Immersion Ion Implantation Treatment

Multilevel resistive switching (RS) of gadolinium oxide (Gd_xO_y) memristors treated by hydrogen plasma immersion ion implantation (PIII) was investigated. Hydrogen ions were implanted at the Pt/Gd_xO_y interface to modify the oxygen-vacancy distribution, which was examined by the X-ray photoelectron spectroscopy. After the hydrogen PIII treatment, a forming process is needed to operate the Gd_xO_y memristors and the RS mechanism is changed from Schottky emission to space-charge-limited conduction. Superior multilevel RS properties such as data retention for more than 10⁴ s at 85°C, and sequentially cycling test for more than 10³ times with a resistance ratio of approximately one order of magnitude between each state are realized, making the future high-density flash memory possible.