Influence of the Ozone Dose Time during Atomic Layer Deposition on the Ferroelectric and Pyroelectric Properties of 45 nm-Thick ZrO2 Films

Research output: Contribution to journalResearch articleContributedpeer-review


  • Bohan Xu - , NaMLab - Nanoelectronic materials laboratory gGmbH (Author)
  • Liam Collins - , Oak Ridge National Laboratory (Author)
  • Kristina M. Holsgrove - , Queen's University Belfast (Author)
  • Thomas Mikolajick - , Chair of Nanoelectronics, NaMLab - Nanoelectronic materials laboratory gGmbH (Author)
  • Uwe Schroeder - , NaMLab - Nanoelectronic materials laboratory gGmbH (Author)
  • Patrick D. Lomenzo - , NaMLab - Nanoelectronic materials laboratory gGmbH (Author)


Over a decade ago, ferroelectricity was discovered in doped HfO2 thin films. The HfO2-based thin films have attracted much attention due to their remarkable scalability and CMOS compatibility. Other than the HfO2-based thin films, the undoped ZrO2 thin films are understudied despite their commonly reported antiferroelectric behavior. However, being of the same fluorite structure as HfO2-based thin films, the undoped ZrO2 also displayed considerable ferroelectricity as demonstrated in recent studies. In this work, 45 nm-thick polycrystalline undoped ZrO2 films are synthesized using atomic layer deposition with different ozone dose times. The ZrO2 films are crystallized after atomic layer deposition at 350 °C without anneals. In general, the longer ozone dose time causes a lower in-plane tensile stress and oxygen vacancy content, which help facilitate an irreversible non-polar tetragonal to polar orthorhombic phase transition with electric-field cycling. However, the lower in-plane tensile stress and oxygen vacancy content also stabilize the monoclinic phase so that a long ozone dose time (>17.5 s) reduces the ferroelectric behavior. After wake-up cycles, the ZrO2 thin film with an ozone dose time of 17.5 s exhibits a remanent polarization of 6 μC·cm-2 and a pyroelectric coefficient of −35 μC·K-1·m-2. Moreover, the wake-up behavior is consistent between the ferroelectric and pyroelectric response. As essential factors in optimizing the growth of fluorite-structure thin films for ferroelectric applications, the in-plane tensile stress and oxygen vacancy content significantly influence the ferroelectric and pyroelectric properties. Additionally, the low thermal budget for processing ferroelectric ZrO2 thin films is valuable for semiconductor back-end-of-line processes.


Original languageEnglish
Pages (from-to)2288–2295
Number of pages8
JournalACS applied electronic materials
Issue number4
Publication statusPublished - 25 Apr 2023

External IDs

WOS 000973020800001
ORCID /0000-0003-3814-0378/work/142256354


DFG Classification of Subject Areas according to Review Boards

Subject groups, research areas, subject areas according to Destatis


  • ferroelectrics, irreversible t- to o-phase transition, ozone dose time, stress, wake-up effect, zirconium oxide, Irreversible t-to o-phase transition, Zirconium oxide, Ozone dose time, Ferroelectrics, Wake-up effect, Stress