Chun-Shiang Wu
Institute
of Electrical Engineering
National Cheng Kung University
Tainan, Taiwan
Resistive Switching Behaviour of
Diode-like Gadolinium Oxide
Resistive Random Access Memory
ICONN 2014 oral presentation
Outline
•
RRAM Introduction
•
Motivation
•
Experimental
•
Results and discussion
•
Advantages
:
nonvolatile memory
Simple structure
Fast switching speed
high density integration
Fabrication compatibility with CMOS technology
•
The matter of filament：
(1) metal
(2) oxygen vacancy
•
Formation or rupture of filament：
(1) Joule heating
(2) Electrochemical metallization
Filamentary theory
| Introduction (2/2) |
motivation | Experimental | Results & discussion | Conclusion |
BE
TE
(-)
(-)
(+)
(+)
e
-O
2-SET (LRS)
RESET (HRS)
Ag Pt Ag+Rare-earth oxide RRAM
Yb
2
O
3
, Nd
2
O
,
Gd
2
O
3
Cubic (a
Gd2O3
= 1.0812 nm ~ 2a
Si
= 0.543 nm)
wide band gap (~5.9 eV)
High-k (k = 14 - 20)
stable in contact with Si
Forming-free
•
Cross-bar arrays → 4F
2
•
cross-talk interference
Electrical properties
measurement
Top & bottom electrodes
E-beam deposition
Annealing
n-Gd
2O
3Deposition
p-Si(111) Wafer Clean
Deposition conditions
Power
100 W
Substrate Temp.
400
oC
Deposition time
20min
Deposition gas
Pure Ar
| Introduction | motivation | Experimental
| Results & discussion (1/4)|
Conclusion |
As-deposited
| Introduction | motivation | Experimental
| Results & discussion (2/4) |
Conclusion |
| Introduction | motivation | Experimental
| Results & discussion (3/4) |
Conclusion |
I-V & Ideal Factor
𝐼 = 𝐼
0exp[
𝑉
𝐷| Introduction | motivation | Experimental
| Results & discussion (4/4) |
Conclusion |
•
Its forming-free process is owing to the initial
exist of oxygen vacancies and metallic Gd.
•
At annealing 800
o
C with N
2
-H
2
atmosphere has
the better RS property due to more oxygen
vacancy in Gd
2
O
3
thin film.
•
The rectified current ratio of LRS in Al/
Gd
2
O
3
/Si is about five orders of magnitude that
suppressing sneak current.
References
• Cho B, Kim T W, Song S, Ji Y, Jo M, Hwang H, Jung G Y and Lee T, “Rewritable Switching of One Diode–One Resistor Nonvolatile Organic Memory Devices”, Adv. Mater. 22, pp. 1228–1232, 2010.
• T.M. Pan and C.H. Lu, “Forming-free resistive switching behavior in Nd2O3, Dy2O3, and Er2O3 films fabricated in full room temperature,” Appl. Phys. Lett., vol. 99, pp. 113509-1–3, September 2011.
• T.M. Pan and C.H. Lu, “Switching behavior in rare-earth films fabricated in full room temperature,” IEEE transactions on electron devices, vol. 59, pp. 956–961, April 2012.
• J.C. Wang, Y.R. Ye, J.S. Syu, P.R. Wu, C.I Wu, P.S. Wang, and J.H. Chang, “Low-power and high-reliability gadolinium oxide resistive switching memory with remote ammonia plasma treatment”, Japanese Journal of Applied Physics, vol. 52, pp. 04CD07-1–4, March 2013
• M.Y. Song, Y. Seo, Y.S. Kim, H.D. Kim, H.M. An, B.H. Park, Y.M. Sung, and T.G. Kim, “Realization of One-Diode–Type Resistive-Switching Memory with Cr–SrTiO3 Film,” Applied Physics Express, vol. 5, pp. 091202-1–3, August 2012.
• K.L. Lin, T.H. Hou, J. Shieh, J.H. Lin, C.T. Chou and Y.J. Lee, “Electrode dependence of filament formation in HfO2 resistive-switching memory,” J. Appl. Phys., vol. 109, pp. 084104-1–7, April 2011.
