Ferroelectricity in Undoped ZrO₂ Thin Films on Pt Electrode Without Post-Annealing Treatment
Bo-Ting Lin1*, Jay Shieh1, Miin-Jang Chen1
1Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
* presenting author:Bo-Ting Lin, email:f02527007@ntu.edu.tw
Here we report the ferroelectricity with a high remnant polarization of 18 μC/cm² in undoped ZrO₂ nanoscale thin films prepared by plasma-enhanced atomic layer deposition (PE-ALD) on the Pt electrode. Significant ferroelectric hysteresis loop was achieved in the as-deposited ZrO₂ thin films without treated with the post-annealing, which is highly beneficial to the device integration. The polarization-electric field hysteresis, the X-ray diffraction structural analysis, and high-resolution transmission electron microscopy confirm the presence of ferroelectric orthorhombic phase in the undoped ZrO₂ films. All the paraelectric, field-driven antiferroelectric, and ferroelectric behaviors of ZrO₂ were observed by changing the film deposition temperature and by performing post-annealing treatment, indicating the tunability of ferroelectricity in undoped ZrO₂ thin films. The result reveals the great potential of the undoped ZrO₂ thin films prepared by the PE-ALD technique for the next-generation non-volatile memories and ultralow-power transistors.

Keywords: Zirconia, Ferroelectricity, Atomic layer deposition, Thin films, TEM