TY - JOUR
T1 - Exploring New Metal Electrodes for Ferroelectric Aluminum-Doped Hafnium Oxide
AU - Ryu, Hojoon
AU - Xu, Kai
AU - Kim, Jinhong
AU - Kang, Sangmin
AU - Guo, Ji
AU - Zhu, Wenjuan
N1 - Funding Information:
Manuscript received February 20, 2019; revised March 19, 2019; accepted March 20, 2019. Date of publication April 10, 2019; date of current version April 22, 2019. This work was supported in part by the National Science Foundation (NSF) under Grant ECCS 16-53241 CAR and in part by the Office of Naval Research (ONR) under Grant NAVY N00014-17-1-2973. The review of this paper was arranged by Editor C. Monzio Compagnoni. (Corresponding author: Wenjuan Zhu.) The authors are with the Department of Electrical and Computer Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 USA (e-mail: hojoonr2@illinois.edu; kaixu86@illinois.edu; jkim686@illinois.edu; smkang@illinois.edu; gj.xjtu@hotmail.com; wjzhu@illinois.edu).
Funding Information:
This work was supported in part by the National Science Foundation (NSF) under Grant ECCS 16-53241 CAR and in part by the Office of Naval Research (ONR) under Grant NAVY N00014-17-1-2973.
Publisher Copyright:
© 2019 IEEE.
PY - 2019/5
Y1 - 2019/5
N2 - 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.
AB - 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.
KW - Ferroelectric devices
KW - ferroelectric films
KW - ferroelectric materials
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U2 - 10.1109/TED.2019.2907070
DO - 10.1109/TED.2019.2907070
M3 - Article
AN - SCOPUS:85064970910
SN - 0018-9383
VL - 66
SP - 2359
EP - 2364
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
IS - 5
M1 - 8682093
ER -