SPICE Model for Dual-Extended Memristor
Zhiyuan Li
1,2
*
, Qingkun Li
1,2
, Dianzhong Wen
1
1
School of Electronic Engineering, Heilongjiang University, Harbin 150080, China
2
Post-doctoral Mobile Stations of Electronic Science and technology, Heilongjiang University, Harbin 150080, China
* Email: lizhiyuan@hlju.edu.cn
Abstract: This paper presents a SPICE model for the
dual-extended memristive device. I-V characteristics for
the dual-extended memristor have been simulated by the
proposed the SPICE model. And the effect of the
parameter variations on the performance has also been
discussed, such as the window function factor p, the
frequency of input signal, and the dimension of the
memristor and so on. Finally, the measurement results
from real devices validate the proposed SPICE model for
the dual-extended memristor.
Keywords: Memristor; Device; SPICE; Model
1. Introduction
Leon Chua theoretically reasoned that memory resistor
(abbreviated as memristor) should be the fourth passive
two-terminal circuit element in 1971 [1]. However, it
was not until in 2008 that Dmitri B. Strukov et al. of
Hewlett Packard (HP) physically realized a memristor
prototype[2], which finally confirming Chua’s theory.
Since the publication of the first physical memristor
devices[2], research efforts related to memristors have
been growing rapidly throughout the world, including a
few of novel memristor structures[3-5], device
models[6-8], and SPICE model[9-11], and so on.
Based on TiO
2
memristor developed by HP [2], a
dual-extended memristor (Pt/TiO
2-x
/TiO
2
/TiO
2+x
/Pt) was
proposed in 2009 by the Professor Dianzhong Wen of
our research-group[5], as shown in Figure 1. Nanoscale
titanium dioxide semiconductor films TiO
2-x
, TiO
2+x
and
TiO
2
were sandwiched between two nanowires Pt,
forming the Pt/TiO
2-x
/TiO
2
/TiO
2+x
/Pt nanostructure
memristor.
Figure 1. Structure of a dual extended memristor
Since the dual-extended memristor can be widely used in
the design of memristor-based systems, this paper
presents a SPICE model for the device based on a SPICE
model that was previously proposed in[9].
2. Device Model of Dual-Extended Memristor
The physical model of the dual-extended memristor is
shown in Figure 2. Doped regions including TiO
2-x
film
or TiO
2+x
film behave as semiconductors, and un-doped
region TiO2 film has an insulating property. The widths
2
0,
x
TiO
w
and
2
0,
x
TiO
w
are modulated depending on the
amount of electric charges passing through the memristor.
With electric current passing in a given direction, this
structure can make that oxygen vacancies and oxygen
ions are injected into or extracted from the main working
layer synchronously when an electric field was applied.
Figure 2. Structure of a dual extended memristor
The total resistance of the memristor, R
mem
, is a sum of
the resistances of the doped and undoped regions,
11 2 2 1 2
() (1 )
mem on on off
xRxR xR xx
(1)
where
1on
,
2on
, and
off
are the resistances of the
device with TiO
2+x
, TiO
2-x
and TiO
2
nano-film for the full
length D respectively. And
2
10,
x
TiO
wD
,
2
20,
x
TiO
wD
.
Thus,
10,/)(
21
xDxxx
(2)
Assuming that ohm’s law is founded,
)()()(
tixRtv
mem
(3)
The speed of the movement of the boundary between the
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