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Opening Remarks- Spintronics for Nonvolatile Electronics -
Hideo Ohno
http://www.csis.tohoku.ac.jp/
Center for Spintronics Integrated Systems Tohoku University, Sendai, Japan
Supported by the FIRST program of JSPS.
2011 Spintronics Workshop on LSIJune 13, 2011
Rihga Royal Hotel Kyoto, Kyoto, Japan
2011 Spintronics Workshop on LSI
2
ChallengesStatic powerDynamic powerInterconnection delayFeature size
NonvolatileSmallEmbedded in interconnectionPart of logic
Making memories
Nonvolatile CMOS Electronics
Comparison of memories
PRAM ReRAM MRAM Spin (STT)RAM FeRAM
Cell Size ~130 F2 4~8 F2 4 F2 4~6 F2 16~40 F2 4~ 64F2 12~25 F2
High Speed
Operation◎ ○ ○ ○ ○ ◎ ○
Nonvolatility - - ○ ○ ○ ○ ○
Endurance
(limitation
of W/E
cycle)
◎
(∞)
◎
(∞)○ ○ ◎ ◎ ○
Lower
power
operation○ ◎ △ △ △
○◎
Next Generation Nonvolatile MemorySRAM DRAM
⇒ ◎
T. Endoh, ITRS Emerging Research Memory Technologies Workshop2010T. Endoh, STS in SEMICON Korea2010 (Invited)
System (Memory) Hierarchy
current near future future
NonvolatileLogic-in-Memory
Magnetic tunnel junction based memory elements to counter dynamic and static power, and interconnection delay
Ohno et al. IEDM 2010
E E
Magnetic Tunnel JunctionA Spintronics Device
2
2
12(TMR) istanceMagnetoRes Tunnel
PP
RRR
P
PAP
−=
−=
Ferromagnet 1 Ferromagnet 2Insulator
Parallel
Antiparallel
Room temperature TMR: Miyazaki and Tezuka (Tohoku U.), J. Mag. Mag. Mat. 1995 and Moodera et al. Phys. Rev. Lett. 1995.
6
two terminal three terminal
Magnetic Tunnel Junction Configurations
nonvolatile, fast and high endurance
MTJ for VLSI: A wish list
1. Small footprint (F nm)2. High output (TMR ratio > 100%) 3. Nonvolatility (∆=E/kBT >40)4. Low switching current (IC0 < F µA)5. Back-end-of-the-line compatibility (350 oC)6. Endurance 7. Fast read & write8. Low resistance for low voltage operation9. Low error rate10. Low cost
E
Parallel Antiparallel
Thermal fluctuationkBT
E
Parallel Antiparallel
Thermal fluctuationkBT
Ic0 and ∆=E/kBT
> kBT
perpendicular
E
Parallel Antiparallel
Thermal fluctuationkBT
E
Parallel Antiparallel
Thermal fluctuationkBT E
Parallel Antiparallel
Thermal fluctuationkBT
E
Parallel Antiparallel
Thermal fluctuationkBT
Ic0 and ∆=E/kBT
( )shape crystallineE K K V= +
( )
E
KVgeI
KVVHME
BC
KS
αµαγ
∝
=
=
=
221
0
S. Ikeda et al., Nat. Mat. 9, 721 (2010), K. Miura et al., MMM 2010
Perpendicular MgO-CoFeB MTJ
SiO2/Si sub.
Ta
Ru
Cr/Au
TaCoFeB
CoFeBMgO
TaRu
40 nm
5 nm
(a)
(c)
(b)
Top electrode
Bottom electrode
interface perpendicularanisotropy
JC0 = 3.8 MA/cm2
(IC0 = 48 μA) E/kBT ~ 40TMR ratio = 110%Ta = 350oC
perpendicular
Scaling
TkEI BC 60for A][ 104.3 30 =×= µα
High and low αKS HMK21
= 0
10
20
30
40
50
60
70
80
90
100
0 0.01 0.02 0.03 0.04 0.05
IC0 = 100 µAIC0 = 50 µAIC0 = 30 µAIC0 = 20 µA
α
E/k B
T
α = 0.015 α = 0.029
α = 0.009
α = 0.006
( )
E
KVgeI
KVVHME
BC
KS
αµαγ
∝
=
=
=
221
0
In-planeCoFeB
α versus Ku
Ref. [1] E. P. Sajitha, et. al., IEEE Transactions on Magnetics, 46, 2056 (2010)[2] S. Mizukami, et. al., App. Phys. Lett., 96, 152502 (2010) [3] A. Barman, et. al., J. App. Phys., 101, 09D102 (2007) [4] J.-M. Beaujour, et. al., Phys. Rev. B., 80, 180415R (2009)[5] N. Fujita, et. al., J. Magn. Magn. Mater., 320, 3019 (2008)[6] S. Ikeda, et. al., Nat. Mat., 9, 721 (2010)
10-31E-3
0.01
0.1
1 CoFeB/Pd/[Co/Pd]x6 [1] Pt/Co/Pt [2] [Co/Pt]xn [3] Pd/Co/Pd/[Co/Ni]x3/Pd/Co/Pd [4] [Co/Pt]x12 [5] Ta/CoFeB/MgO [6]
10010-1 101
Dam
ping
par
amet
er, α
Ku (x105 J/m3)10-2
13
14
How small can we go?
CoPtCr-SiO2, Takei et al., Fuji Electric review 55 (2009) 6..
Center for Spintronics Integrated Systems
CSIS home page http://www.csis.tohoku.ac.jpTohoku University
Support office
Spintronics materials Shoji Ikeda (Tohoku Univ.)
Yasuo Ando (Tohoku Univ.)Spintronics devices
Fumihiro Matsukura (Tohoku Univ.)New spintronics materials and devices
Nobuyuki Ishiwata ( NEC )Spintronics processing
Takahiro Hanyu (Tohoku Univ.)Spintronics logic design and IP development
Tetsuo Endoh (Tohoku Univ.)Design tool development for spintronics VLSI
Tadahiko Sugibayashi ( NEC )Spintronics VLSI demonstration
Advisory Committee
Technical Advisory Committee
Steering Committee
Tsukuba site : Tsukuba Innovation Arena (TIA) Participating organization :Tohoku University, NEC, Hitachi, ULVAC,
National Institute of Material Science,University of Tokyo
Collaborating organization : AIST, JST
Center for Spintronics
Integrated Systems (CSIS)Director: Hideo OhnoDeputy Director: Tetsuo Endoh, Naoki Kasai
Funded by the FIRST Program of JSPS