Effect of capping layer on the ferroelectricity of hafnium oxide

Jui Hsuan Chang, Chen Gui Zheng, Hsuan Han Chen, Pei Tien Chen, Cun Bo Liu, Kai Yang Huang, Hsiao Hsuan Hsu*, Chun Hu Cheng, Wu Ching Chou, Su Ting Han

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


In this work, we investigate the effect of a capping layer of aluminum oxide (AlOx) on dopant-free hafnium-oxide (HfO2) ferroelectric layer. According to our experimental results, the AlOx-capped HfO2 ferroelectric capacitor exhibits the significant improvement on ferroelectric polarization strength and also presents a comparable electrical stress resistance in comparison with control HfO2 ferroelectric capacitor with a very weak ferroelectric hysteresis. An additional nitrogen treatment on AlOx capping layer effectively alleviate the stress-induced generation of defect traps near the interface of tantalum nitride (TaN) electrode under negative-bias voltage stress. Therefore, the performance improvement can be ascribed to the introduction of AlOx capping layer and well-controlled nitrogen plasma treatment to improve interface traps and stabilize the ferroelectric phase transformation during high-temperature annealing process.

Original languageEnglish
Article number139274
JournalThin Solid Films
Publication statusPublished - 2022 Jul 1


  • Aluminum Oxide
  • Capping Layer
  • Ferroelectric Polarization
  • Hafnium Oxide
  • Power Consumption

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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