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This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TNANO.2017.2661818, IEEE
Transactions on Nanotechnology
Abstract—In this paper, electrical characteristics of an
HfO
2
-based resistive switching memory device are investigated
before and after -ray radiation with various total ionizing doses
(TIDs). The device can still function properly even irradiated with
a TID of 20 Mrad(Si).
The small changes of resistance states and
set/reset voltages induced by -ray radiation can hardly influence
the proper function of the device. The -ray radiation does not
significantly degrade both retention and endurance
characteristics even after a high-TID exposure. The radiation
effects on the resistive switching memory device show little
dependence on cell area. The results suggest that the HfO
2
-based
resistive switching memory device has good -ray
radiation-resistant capability.
Index Terms—Resistive switching, hafnium oxide, radiation, γ
ray, total ionizing dose.
I. I
NTRODUCTION
ECENTLY, resistive switching memory device as one of
the most promising candidates for nonvolatile memory
application has attracted much attention for its fast speed, high
reliability, low power consumption, and simple structure [1-3].
One potential future application of resistive switching memory
device is in aerospace or nuclear industry. In aerospace and
nuclear environment, energetic particles transmitting in
solid-state material may produce electron-hole pairs (ionization)
and displacement atoms (or displacement damage) [4, 5]. ray
is popularly used for the total ionizing dose (TID) study. γ-ray
radiation can cause ionization effect and weak displacement
damages. Unlike traditional floating gate memories, in which it
is well established that electron-hole pairs produced by γ rays
could be trapped by the floating gate oxide, resulting in oxide
degradation and electric field change [6], the γ-ray radiation
This work has been financially supported by NSFC under projects No.
61274086 and No. 61404022.
S. G. Hu, Y. Liu, Q. Yu and L. J. Deng are with the State Key Laboratory of
Electronic Thin Films and Integrated Devices, University of Electronic Science
and Technology of China, Chengdu 610054, China (e-mail:
yliu1975@uestc.edu.cn).
T. P. Chen is with the School of Electrical and Electronic Engineering,
Nanyang Technological University, Singapore 639798 (e-mail:
echentp@ntu.edu.sg).
Qi Guo, Yu-dong Li and Xing-yao Zhang are with
the Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of
Sciences, Urumchi 830011, China.
Y. Yin and Sumio Hosaka are with the Graduate School of Engineering,
Gunma University, 1-5-1Tenjin, Kiryu, Gunma 376-8515, Japan.
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effects on filament-type resistive memory is still controversial.
Recently, radiation effects on resistive switching memory
devices were studied [7-10].Y. Wang et.al has demonstrated
that the Cu-doped HfO
2
-based switching memory devices are
immune to Co-60 γ rays up to a total ionizing dose (TID) of 360
krad(Si), and the small changes of resistance states and set/reset
voltages were attributed to the displacement damages created
by γ rays [7]. L. Zhang et.al reported that TaO
x
-based resistive
switching memory devices in high-resistance state with large
area and thick oxide layer were vulnerable to Co-60 γ rays and
more possible to change into the low-resistance state [8].
In this work, radiation effects on HfO
2
-based resistive
switching memory devices with different cell areas are
investigated. The irradiated devices function properly, without
significant degradation in the set and reset voltages, resistance
states, endurance and retention characteristics. The superior
radiation-resistant capability of the HfO
2
-based resistive
switching memory device makes it a promising candidate for
the application in radiation environment.
II.
EXPERIMENTAL DETAILS
The HfO
2
-based resistive switching memory device is based
on a metal-insulator-metal (MIM) structure with a thin HfO
2
layer as the insulator. The MIM structure was fabricated onto a
400 nm SiO
2
film that had been thermally grown on a p-type
silicon wafer. The bottom electrode was formed by depositing a
100 nm Au/10 nm Ni layer on the SiO
2
film using
electron-beam evaporation. A HfO
2
thin film of ~80 nm
thickness was deposited onto the Ni layer by RF (13.6MHz)
magnetron sputtering of a HfO
2
target (>99.99% in purity). A
150 nm Au/10 nm Ni layer was finally deposited onto the HfO
2
film by electron-beam evaporation to form the top electrodes
with diameters from 10 m to 100 m. Dies with different
electrode areas were cut from the wafer. The dies were
assembled on 28-pin dual in-line package (DIP) ceramic bases.
And then the top electrodes and the common bottom electrodes
were bonded to the corresponding lead terminals on the ceramic
bases with Au wires. The wire bonding process was carried out
in Integrated Service Technology, Inc. The pins of the devices
were floated during radiation exposure. Electrical
characteristics were measured with a Keithley-4200
semiconductor characterization system at room temperature.
III. R
ESULTS AND
DISCUSSION
Twelve devices were exposed to Co-60 rays of various
TIDs. The current – voltage (I-V) characteristics of the twelve
γ-ray radiation effects on an HfO
2
-based
resistive memory device
S. G. Hu, Y. Liu, T. P. Chen, Qi Guo, Yu-dong Li, Xing-yao Zhang, L. J. Deng, Q. Yu,
Y. Yin and
Sumio Hosaka