Mechanism of Oxygen Vacancy Filament-Based Resistive Switching in Non-polar Hf0.5Zr0.5O2-δ Thin Films

The development of complementary metal-oxide-semiconductor memory devices is based on the stability of the switching process, which necessitates the control of defect concentrations. In this work, hafnium zirconium oxide Hf0.5Zr0.5O2-delta thin films with a TiN/Hf0.5Zr0.5O2-delta/Au structure with a thickness of 40 nm were synthesized and analyzed to study the effect of oxygen deficiency in the oxide layer on the switching dynamics and charge transport mechanism of the device. A typical bipolar resistive switching behavior was obtained with an ON/OFF ratio of 130, in contrast to the often-invoked performance of the material as a ferroelectric tunnel junction in ultrathin films. The reproducibility and uniformity of the device were studied by performing 100 continuous DC cycles. By fitting the experimental data to different conduction mechanisms, the electrical conductivity in the high-resistance state was dominated by Schottky emission. In contrast, the conductivity in the low-resistance state showed a linear current-voltage characteristic that indicated the formation of an oxygen vacancy filament. The endurance and retention were observed under pulsed write/erase operation and led to endurance cycles of 10(4) and a retention time of 10(5) s.

Automated summary

The effect of oxygen deficiency in Hf0.5Zr0.5O2-delta thin films on the switching dynamics and charge transport mechanism of a device was studied. Bipolar resistive switching behavior was observed, and different conduction mechanisms were identified.