Forming-Free Grain Boundary Engineered Hafnium Oxide Resistive Random Access Memory Devices

Stefan Petzold, Alexander Zintler, Robert Eilhardt, Eszter Piros, Nico Kaiser, Sankaramangalam Sharath, Tobias Vogel, Márton Major, Keith Patrick McKenna, Leopoldo Molina-Luna, Lambert Alff

Research output: Contribution to journalArticlepeer-review


A model device based on an epitaxial stack combination of titanium nitride (111) and monoclinic hafnia (11 (Formula presented.)) is grown onto a c-cut Al 2O 3-substrate to target the role of grain boundaries in resistive switching. The texture transfer results in 120° in-plane rotated m-HfO 2 grains, and thus, in a defined subset of allowed grain boundary orientations of high symmetry. These engineered grain boundaries thread the whole dielectric layer, thereby providing predefined breakdown paths for electroforming-free resistive random access memory devices. Combining X-ray diffraction and scanning transmission electron microscopy (STEM)–based localized automated crystal orientation mapping (ACOM), a nanoscale picture of crystal growth and grain boundary orientation is obtained. High-resolution STEM reveals low-energy grain boundaries with facing ((Formula presented.)) and ((Formula presented.) 21) surfaces. The uniform distribution of forming voltages below 2 V—within the operation regime—and the stable switching voltages indicates reduced intra- and device-to-device variation in grain boundary engineered hafnium-oxide-based random access memory devices.

Original languageEnglish
Article number1900484
JournalAdvanced Electronic Materials
Early online date5 Aug 2019
Publication statusE-pub ahead of print - 5 Aug 2019

Bibliographical note

© Authors, 2019


  • grain boundary engineering
  • hafnium oxide
  • resistive switching memory
  • texture transfer
  • transmission electron microscopy

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