VDEC設立20周年記念行事
東京大学武田先端知ビル、2017年1月20日

スピントロニクス素子と集積回路応用
大野英男
東北大学 電気通信研究所
東北大学 省エネルギー・スピントロニクス集積化システムセンター
東北大学 スピントロニクス学術連携研究教育センター
東北大学 国際集積エレクトロニクス研究開発センター
東北大学 原子分子材料科学高等研究機構
Tetsuo Endoh, Takahiro Hanyu, Shunsuke Fukami, Shoji Ikeda, Hideo Sato,
Shun Kanai, Fumihiro Matsukura and the CSIS teamWork supported in part by the FIRST Program from JSPS, ImPACT from JST,and by the R & D for Next-Generation Information Technology of MEXT

http://www.csis.tohoku.ac.jp/

Current Working Memories
2
DRAM: dense, 6F
2
SRAM: fast, 200F
VolatileToward Nonvolatile CMOS VLSI

Present LogicVLSIs
Logic

Volatile memory

Logic VLSIs withSpintronics Memory
Non-volatile memory
Logic

Si sub.

Spintronics
Logic-in-Memory
VLSIs

Leakagecurrent

Zero standby power of memory
by non-volatile spintronics
devices

Low Power Consumption

Non-volatile memory

Logic
Si sub.
Logic-in-Memory Architecture by fusion
between logic circuits and MTJs
（Reduction of device number andinterconnect wiring length）

Low Power, High Performance, Low Cost

Si sub.

Nonvolatile memory that isscalablefast
virtually infinite endurance
back-end-of-line compatible
low resistanceTwo versus Three terminal: operation window
Two-terminal

Three-terminal(Magnetic Tunnel Junction)

Readmargin

Read Write
margin margin
READRead

TDDBVWRITE

ReadWriteTDDBWrite
margin

VWrite6‐8 F2

12 F2EM V

Three-terminal: Different READ and WRITE current path
 High-speed operation, Simple and small-area peripheral circuits
Wide waveform tolerance owing to the large operation window Long lifetime  Much less stress on tunnel barrier Low error rate  No read disturbance, overdrive possible• TDDB : Time-dependent dielectric breakdown• EM : Electromigration

S. Fukami et al. IEEE Trans. Magn. 50, 3401006 (2014).

2 terminal device
Magnetic Tunnel Junction(Spin‐transfer torque)Ic0 and =E/kBT
perpendicularParallel

E  K eff V2 e
IC 0 
K eff VB g



EK eff  K eff

Parallel

Antiparallel

AntiparallelE

Thermal fluctuation

kBT

Thermal fluctuationE  K shape  K crystalline V

EkBTPerpendicular MgO-CoFeB MTJ
JC0 = 3.8 MA/cm2(IC0 = 48 μA)
E/kBT ~ 40
TMR ratio = 110%Ta = 350oC
1.6 nm0.9 nm
1.0 nmCo20Fe60B20

interface perpendicularanisotropy

S. Ikeda et al., Nature Mat. 9, 721 (2010)

E/kBT

E/kBT

1009080706050403020
100series1series2
APL 2012
calculation

010 20 30 40 50 60 70 80
Junction diameter (nm)H. Sato et al., Appl. Phys. Lett. 105, 062403 (2014)

STT-MRAM

H. Koike et al. IMW2016

Qualcomm, GlobalFoundries, TSMC, TDK Headway, Toshiba, Hynix, Avalanche, …
TEL, AMAT, CANON-ANELVA, …
Tohoku University, IMEC

Switching current versus switching speed
Precessional switching(short current pulse)1 I  IC0  A

Thermally activated switching(long current pulse)

1P-AP

600400D (nm)IC (A)

2008261414161820-200-400

AP-P-9-8

10 10-7-6-5-4

10 10 10 10 10
 (s)N. Ohshima et al., 76th JSAP fall meeting, 14p‐2J‐8.

-3-2

10 10-1

Background Write
PLWL
CMOS
latch
MTJBL

STT‐MRAM cell/BL

Data from BL
Data from CMOS latch
Write to CMOS latch
Cell 1MTJswitchCell 2tcw tcw

timeT. Ohsawa et al., Symp. VLSI Circuits, pp. C110-C111, June 2013. @Endoh Gr. of Tohoku Univ.

Ternary CAM Cell
T. Hanyu Group
CMOS-based (12T)
one-bitstorage(Volatile)

Comparison
logic

one-bitstorage(Volatile)

Spintronics & CMOS (2T-2MTJ)MTJ devices(Nonvolatile)
Comparison
logic

Area, Activity and Standby → Low Power

3 terminal device
Spin‐Orbit Switchingfor SOT‐MRAM

Spin-Orbit Torque (SOT) switching

1. In-plane current  Spin accumulation (through SOI)
2. Accumulated spin  Torque (=Spin Orbit Torque; SOT)
3. Torque  Magnetization switchingExperiment
N = 20 Type X

100(a)

Type Y

20 mT Type Y(STT switching)

Switching probability PSW (%)

50

SOT switching in Type X(and Type Z) is promisingfor GHz-class operation.
S. Fukami et al., Symp. on VLSI Tech. T06-5 (2016).

Type Xp = 100 ns

0100(b)50

p = 10 ns

0100(c)50

p = 1 ns

0100(d)50

p = 0.5 ns00

123

1142Current density (10 A/m )5(Co/Ni)/(Pt/Mn) SOT Device
tPtMn = 8 nm (biased)
H=0RH

END START0.2 START END-40 -30 -20 -10 0

10 20 30 40

ICH (mA)-40 -30 -20 -10 0

10 20 30 40

IMAX (mA)
8121620242832
364044

ICH (mA)

Change in RH varies gradually with IMAX.
= Magnetization state can be controlled in an analogue manner bythe ICH.

… Function of synapse  Neuromorphic computing (AI)S. Fukami et al., Nature Mater. 15, 535 (2016).

 Recovery of direction cosine confirmed.
 Difference from ideal value is due to variation ofdynamic range

Non-volatile CMOS VLSIs with spintronics

600MHzNonvolatile TCAM1Mb Array Three
MTJ/CMOS Latch(Most compact TCAM Terminal DW Cell
(Fastest nonvolatile latch)cell, 4T-2MTJ)(High endurance)(IEDM 2011）（VLSI 2011）(VLSI 2012)

First Auto Design
Tool forSpintronics CMOS
(2011）

Nonvolatile GPU(Largest Scale
Spintronics Random
Logic 500kgate/chip)（ISSCC 2013）

Nonvolatile
microcomputer(First nonvolatile
microcomputer)（ISSCC 2014）

Nonvolatile FPGA
with TSV(First 3D Spintronics
CMOS Processor)（VLSI 2012）

1.5nsec / 1Mbit
Embedded MRAM
(Fastest nonvolatile
1Mbit memory)（VLSI 2013）

On 300 mm wafers

Development framework for spintronics devices
Tohoku University

Center for Innovative
Integrated Electronic Systems(CIES)(Director : Tetsuo Endoh)

Center for Spintronics Integrated
Systems (CSIS)(Director : Hideo Ohno)+Development of key technologies forspintronics materials and devices
using 3in process tools

Development of spintronics materials, devices
and integration technologies
using 300 mm-wafer process tools

Paradigm Shift by Spintronics
High Speed

High power

Storage capacity

Low power
Cache Memory