Thermal stability of antiferroelectric-like Al:HfO2 thin films with TiN or Pt electrodes

HfO2-based antiferroelectric-like thin films are increasingly being considered for commercial devices. However, even with initial promise, the temperature sensitivity of electrical properties such as loss tangent and leakage current remains unreported. 50 nm thick, 4 at. % Al-doped HfO2 thin films w...

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Bibliographic Details
Published in:Applied physics letters 2022-06, Vol.120 (23)
Main Authors: Payne, Alexis, Alex Hsain, H., Lee, Younghwan, Strnad, Nicholas A., Jones, Jacob L., Hanrahan, Brendan
Format: Article
Language:English
Subjects:
Antiferroelectricity
Applied physics
Atomic layer deposition
Atomic layer epitaxy
Capacitance
Capacitors
Dielectric properties
Electrical properties
Electrical properties and parameters
Electrodes
Energy storage
Hafnium oxide
Leakage current
Materials properties
MATERIALS SCIENCE
Microelectronics
Permittivity
Room temperature
Tangents
Temperature
Thermal stability
Thin films
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Summary:HfO2-based antiferroelectric-like thin films are increasingly being considered for commercial devices. However, even with initial promise, the temperature sensitivity of electrical properties such as loss tangent and leakage current remains unreported. 50 nm thick, 4 at. % Al-doped HfO2 thin films were synthesized via atomic layer deposition with both top and bottom electrodes being TiN or Pt. A study of their capacitance vs temperature showed that the Pt/Al:HfO2/Pt had a relative dielectric permittivity of 23.30 ± 0.06 at room temperature with a temperature coefficient of capacitance (TCC) of 78 ± 86 ppm/°C, while the TiN/Al:HfO2/TiN had a relative dielectric permittivity of 32.28 ± 0.14 at room temperature with a TCC of 322 ± 41 ppm/°C. The capacitance of both devices varied less than 6% over 1 to 1000 kHz from −125 to 125 °C. Both capacitors maintained loss tangents under 0.03 and leakage current densities of 10−9–10−7 A/cm2 between −125 and 125 °C. The TiN/Al:HfO2/TiN capacitor maintained an energy storage density (ESD) of 18.17 ± 0.79 J/cm3 at an efficiency of 51.79% ± 2.75% over the −125 to 125 °C range. The Pt/Al:HfO2/Pt capacitor also maintained a stable ESD of 9.83 ± 0.26 J/cm3 with an efficiency of 62.87% ± 3.00% over the same temperature range. Such low losses in both capacitors along with their thermal stability make antiferroelectric-like, Al-doped HfO2 thin films a promising material for temperature-stable microelectronics.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0083656