nrp symposium presentation - ntu singapore · 2019. 4. 25. · nrp symposium presentation spms04 li...
TRANSCRIPT
NRP SYMPOSIUM PRESENTATION
SPMS04
Li Jiang Rong
River Valley High School
Spin Orbit Torque-Based Synaptic Devices in an Artificial
Neural Network
2
1.RATIONALE
Significance of Project
SMALLER devices withHIGHER data density
4
8-Bit Data
1 1 1 1 1 1 1 100000000
ConventionalElectronics Spintronics
VS
INCREASINGpower consumption
5
Transistors Power
2.AIMS
Objectives of Project
6
Device Size Dependence
Device Size
7
(100 nm – 800 nm) No. of Resistance States
Hopfield Network
8
Character Recognition
Simulation of SOT devices
3.METHODOLOGY
Experimental Procedures
9(Device Size Dependence)
10
1 2
SOT Devices
(Device Size Dependence)
11
Magnetron Sputtering
1
Electron Beam Lithography Ion Milling
(Device Size Dependence)
12
MagnetronSputtering
Si/SiO2 Substrate
1
[
[[[
Ta[Co/Pt]4
Ta
Electron Beam Lithography Ion Milling
(Device Size Dependence)
13
Electron Beam Exposure
1
Electron BeamLithography
Substrate
Positive Resist
Substrate
Negative Resist
Substrate
Substrate Substrate
Substrate
Magnetron Sputtering Ion Milling
(Device Size Dependence)
14
Removing material to a desired depth (17.2 nm)
1
Ion Milling
Substrate
Magnetron Sputtering
Electron Beam Lithography
(Device Size Dependence)
15
2
Computer with
LabVIEW programme
Keithley 2400 source meter to send Iwrite pulses
Sample
Electromagnets
Motor with 1.8°
rotation step size
Field-Induced
Current-Induced
&
Arduino to control
motor
(Device Size Dependence)
16
2
Field-Induced
Current-Induced
&
(Device Size Dependence)
4.RESULTS ANALYSIS
Discussion of Project
17(Device Size Dependence)
18
Field-Induced
-10 -8 -6 -4 -2 0 2 4 6 8 10
-1
0
1
2
3
4
5
6
7
()
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
-8 -6 -4 -2 0 2 4 6 8
0
1
2
3
4
5
6
7
8
9
()
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
f) h)-8 -6 -4 -2 0 2 4 6 8
0
1
2
3
4
5
6
7
8
(o)
93.6
91.8
90.0
88.2
86.4
H (kOe)
RH (
)
-8 -6 -4 -2 0 2 4 6 8
-2
-1
0
1
2
3
4
5
6
7
(o)
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
a) b)
-8 -6 -4 -2 0 2 4 6 8
-1
0
1
2
3
4
5
6
7
(o)
93.6
91.8
88.2
86.4
84.6
RH (
)
H (kOe)
c)
-8 -6 -4 -2 0 2 4 6 8
2
3
4
5
6
7
8
9
()
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
d)
-8 -6 -4 -2 0 2 4 6 8
0
1
2
3
4
5
6
7
8
9
()
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
e)
-8 -6 -4 -2 0 2 4 6 8
0
1
2
3
4
5
6
7
8
9
()
93.6
91.8
90.0
88.2
86.4
RH (
)
H (kOe)
g)
(Device Size Dependence)
19
Current-Induced
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
RH (
)
J (107 A/cm
2)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
RH (
)
J (107 A/cm
2)
a) b)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
RH (
)
J (107 A/cm
2)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
RH (
)
J (107 A/cm
2)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
J (107 A/cm
2)
RH (
)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
RH (
)
J (107 A/cm
2)
e) f) g) h)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
RH (
)
J (107 A/cm
2)
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-3.6
-3.4
-3.2
-3.0
-2.8
-2.6
-2.4
RH (
)
J (107 A/cm
2)
c) d)
(Device Size Dependence)
3.METHODOLOGY
Experimental Procedures
20(Hopfield Network)
21
1
0 5 10 15 20 25 30
0
50
100
150
200
250
300
350
400
450
Nu
mbe
r o
f S
yn
apse
s
Number of Neurons
300 synapses needed in a 5x5 block pattern
(Hopfield Network)
22
2
SOT devices as synaptic weights
(Hopfield Network)
23
3
SOT devices as synaptic weights
-15 -10 -5 0 5 10 15
-1
0
1
2R
H (
)
J (107 A/cm
2)
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
(
a.u
.)
(Hopfield Network)
4.RESULTS ANALYSIS
Discussion of Project
24(Hopfield Network)
25
Hopfield Network3
Character recognition of letters ‘R’, ‘V’, ‘H’ and ‘S’
(Hopfield Network)
26
Hopfield Network3
Character recognition of letters ‘R’, ‘V’, ‘H’ and ‘S’
(Hopfield Network)
27
5.CONCLUSION
Future Implications of Project
• Engineer devices with specific switching characteristics
• Work towards energy-efficient brain-inspired computing
28
References
29
1. Kurenkov, C. Zhang, S. DuttaGupta, S. Fukami, H. Ohno. (March, 2017). Device-size
dependence of field-free spin-orbit torque induced magnetization switching in
antiferromagnet/ferromagnet structures. Applied Physics Letters, 110, 092410.
2. William A. Borders, Hisanao Akima et al. (December, 2016). Analogue spin-orbit torque
device for artificial-neural-network-based associative memory operation.Applied
Physics Express 10, 013007.
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THANK YOU!