Exploring New Metal Electrodes for Ferroelectric Aluminum-Doped Hafnium Oxide

Hojoon Ryu, Kai Xu, Jinhong Kim, Sangmin Kang, Ji Guo, Wenjuan Zhu

Research output: Contribution to journalArticlepeer-review


In this paper, we explore new metal electrodes for ferroelectric capacitors based on Al-doped HfO2. We find that Ti/Pd, Ti/Au, and W top electrodes can induce much higher remanent polarization as compared to the traditional TiN top electrode. The endurance of the capacitors with Ti/Pd electrodes is also much better than that with TiN and W electrodes. These results indicate that Ti/Pd is a very promising candidate for ferroelectric Al-doped HfO2. In addition, we find that the remanent polarization reaches maximum when the annealing temperature is around 900 °C-950 °C. At a given annealing temperature, the optimal Hf-to-Al cycle ratio corresponding to the highest remanent polarization is around 23:1. With optimized process conditions, we demonstrate high-performance Ti/Pd gated ferroelectric Al-doped HfO2 capacitors with remanent polarization up to 20 μC/cm2, endurance higher than 108 cycles, and retention over ten years at room temperature. Another interesting feature of the ferroelectric capacitors with Ti/Pd electrodes is high tunability of polarization by external pulses, which will be important for neurosynaptic computing applications.

Original languageEnglish (US)
Article number8682093
Pages (from-to)2359-2364
Number of pages6
JournalIEEE Transactions on Electron Devices
Issue number5
StatePublished - May 2019
Externally publishedYes


  • Ferroelectric devices
  • ferroelectric films
  • ferroelectric materials

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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