Abstract
The oxygen diffusion rate in hafnia (HfO2)-based resistive memory plays a pivotal role in enabling nonvolatile data retention. However, the information retention times obtained in HfO2 resistive memory devices are many times higher than the expected values obtained from oxygen diffusion measurements in HfO2 materials. In this study, we resolve this discrepancy by conducting oxygen isotope tracer diffusion measurements in amorphous hafnia (a-HfO2) thin films. Our results show that the oxygen tracer diffusion in amorphous HfO2 films is orders of magnitude lower than that of previous measurements on monoclinic hafnia (m-HfO2) pellets. Moreover, oxygen tracer diffusion is much lower in denser a-HfO2 films deposited by atomic layer deposition (ALD) than in less dense a-HfO2 films deposited by sputtering. The ALD films yield similar oxygen diffusion times as experimentally measured device retention times, reconciling this discrepancy between oxygen diffusion and retention time measurements. More broadly, our work shows how processing conditions can be used to control oxygen transport characteristics in amorphous materials without long-range crystal order.
| Original language | English |
|---|---|
| Pages (from-to) | 2372-2381 |
| Number of pages | 10 |
| Journal | Materials Horizons |
| Volume | 11 |
| Issue number | 10 |
| DOIs | |
| State | Published - Mar 20 2024 |
Funding
The work at the University of Michigan was supported by the National Science Foundation under Grant no. ECCS-2106225 and startup funding from the University of Michigan College of Engineering. Y. L. acknowledges the support of an Intel Rising Star Gift. A. V. I. was partly supported by the DOE Office of Science Research Program for Microelectronics Codesign (sponsored by ASCR, BES, HEP, NP, and FES) through the Abisko Project, PM Robinson Pino (ASCR). The work at the State University of New York, University at Albany and NY CREATES was supported by the Air Force Research Laboratory under agreement numbers FA8750-21-1-1018 and FA8750-21-1-1019. The U.S. Government may reproduce and distribute reprints for Governmental purposes, despite any copyright notation. The views and conclusions expressed herein are solely those of the authors and do not necessarily reflect the official policies or endorsements of the Air Force Research Laboratory or the U.S. Government. The ToF-SIMS measurements were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility, and using instrumentation within ORNL's Materials Characterization Core provided by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The authors acknowledge Wei D. Lu (University of Michigan), Yang Zhang (University of Michigan), A. Alec Talin (Sandia National Laboratories), Jonathan Ihlefeld (University of Virginia), Nicole Thomas (Intel), and Seung Hoon Sung (Intel) for helpful discussions on this research. The authors acknowledge the financial support from the University of Michigan College of Engineering and NSF grant no. DMR-0420785, and technical support from the Michigan Center for Materials Characterization. Atomic laser deposition was conducted at the University of Michigan, Lurie Nanofabrication Facility.