itrs emerging technology review, 12 july 2008 contact: sj allen, [email protected] 1 spin torque...
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ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer Technology
S. James AllenUC Santa Barbara
• Science
• TechnologySpin Torque Transfer – RAM, STT-RAM
Spin Torque Transfer Nano-oscillators Spin logic devices
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer Technology
Mark Rodwell UC Santa BarbaraBob Buhrman CornellStu Wolf U. VirginiaH. Ohno Tohoku UniversityNick Rizzo Free ScaleYiming Huai GrandisBill Rippard NISTSteve Russek NISTEli Yablonovitch UC BerkeleyAjey Jacob Intel
With input from
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer Technology
• Science
• TechnologySpin Torque Transfer – RAM, STT-RAM
Spin Torque Transfer Nano-oscillators Spin logic devices
From R. A. Buhrman, “Spin Torque Effects in Magnetic Nanostructures”, Spintech IV, 2007
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Heisenberg exchange
• Giant magneto resistance
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Heisenberg exchange
• Giant magneto resistance
• Spin transfer torque
Ef , 1-band
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Ferromagnet FerromagnetNo
n-m
agn
etic
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Heisenberg exchange
Ef , 1-band
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Anti-ferromagnetic Anti-ferromagnetic
Ferromagnetic
Ferromagnetic
Ferromagnet Ferromagnet
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Giant magneto resistance
Ef , 1-band
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
2
0 2
1 cos/
(1 )I V G G
P
P
2
2
( (0)) 2
0 (1 )
R R
R
P
P
P = 1, ideal, perfect spin valve
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
H. Ohno, “Spintronics” Seminar, UCSB May, 2008
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
H. Ohno, “Spintronics” Seminar, UCSB May, 2008
2
2
( (0)) 2
0 16
( )
R R
R
P
P
P = 1, ideal, perfect spin valve
0.87P
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
H. Ohno, “Spintronics” Seminar, UCSB May, 2008
P = 1, ideal, perfect spin valve
0.6P
Fixed SyF
FreeM. Hosomi, et al., “A novel nonvolatile memory with spin torque transfer magnetization switching: spin-ram”, Electron Devices Meeting,2005. IEDM Technical Digest. IEEE International, pp. 459-462.
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Fre
e
dm
dt
Effective field
Damping
o AHdm
mdt
dmm
dt
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Fixed
Fre
e
-J
edm
dt
dm
dt
Slonczewski torque
Effect
Effective field
Damping
/
ive magnetic field/
o A
B
S
B
S
p
dmm H
dt
dmm
dt
J em m
t M
J em
t Mp
P
P
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer: Science
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Fixed
Fre
e
-J
edm
dt
dm
dt
Slonczewski torque
Effecti
Effective field
Damping
/
ve magnetic fie d/
l
o A
B
S
B
S
p
dmm H
dt
dmm
dt
J em m
t M
J em
t Mp
P
P
dm
dtJ
• Precession• Switching• Damping
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer Technology
• Science
• TechnologySpin Torque Transfer – RAM, STT-RAM
Spin Torque Transfer Nano-oscillators Spin logic devices
From R. A. Buhrman, “Spin Torque Effects in Magnetic Nanostructures”, Spintech IV, 2007
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- STT-RAM
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Fixed
Fre
e
-J
edm
dt
dm
dt
Slonczewski torque
Effecti
Effective field
Damping
/
ve magnetic fie d/
l
o A
B
S
B
S
p
dmm H
dt
dmm
dt
J em m
t M
J em
t Mp
P
P
dm
dtJ
• Precession• Switching• Damping
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- STT-RAM
T. Kawahara, R. Takemura, K. Miura, J. Hayakawa, S. Ikeda, Y.M. Lee, R. Sasaki, Y. Gotot, K. Ito, T. Meguro, F. Matskura, H. Takahash, H. Matsuoka and H. Ohno, “2 Mb SPRAM (Spin-Transfer Torque RAM) with bit-by-bit bi-directional current write and parallelizing-direction current read”, IEEE J Solid-State Circuits, 43, 109 (2008).
~ 200 A
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Conventional MRAM (toggle) and Spin Torque MRAM
H field produces torque to reverse free layer. Spin polarized current produces torque to reverse free layer.
•Need Isw ≈ 40 mA/bit for 0.4 um x 1.0 um.•Isw constant for smaller bits.
•Isw < 1 mA/bit for 0.06 m x 0.12 m bit.•Isw reduces as bit scales smaller.
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2005
M. Hosomi, H. Yamagishi, T. Yamamoto, K. Bessho, Y. Higo, K. Yamane, H. Yamada, M. Shoji, H. Hachino, C. Fukumoto, H. Nagao, H. Kano, “A novel nonvolatile memory with spin torque transfer magnetization switching: spin-ram”, Electron Devices Meeting,2005. IEDM Technical Digest. IEEE International, pp. 459-462.
Fixed SyF
Free
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2005
M. Hosomi, H. Yamagishi, T. Yamamoto, K. Bessho, Y. Higo, K. Yamane, H. Yamada, M. Shoji, H. Hachino, C. Fukumoto, H. Nagao, H. Kano, “A novel nonvolatile memory with spin torque transfer magnetization switching: spin-ram”, Electron Devices Meeting,2005. IEDM Technical Digest. IEEE International, pp. 459-462.
CMOS driver 100 100 nm
S. Ikeda, J.Hayakawa, Y.M. Lee, F. Matsukura, Y. Ohno, T. Hanyu and H. Ohno, “Magnetic tunnel junctions for spintronic memories and beyond”, IEEE Trans Elec. Dev. 54, 991 (2007).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2005
M. Hosomi, H. Yamagishi, T. Yamamoto, K. Bessho, Y. Higo, K. Yamane, H. Yamada, M. Shoji, H. Hachino, C. Fukumoto, H. Nagao, H. Kano, “A novel nonvolatile memory with spin torque transfer magnetization switching: spin-ram”, Electron Devices Meeting,2005. IEDM Technical Digest. IEEE International, pp. 459-462.
CMOS sensing > 0.2 V
S. Ikeda, J.Hayakawa, Y.M. Lee, F. Matsukura, Y. Ohno, T. Hanyu and H. Ohno, “Magnetic tunnel junctions for spintronic memories and beyond”, IEEE Trans Elec. Dev. 54, 991 (2007).
Read ~ 0.2 V < write!
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2005
M. Hosomi, H. Yamagishi, T. Yamamoto, K. Bessho, Y. Higo, K. Yamane, H. Yamada, M. Shoji, H. Hachino, C. Fukumoto, H. Nagao, H. Kano, “A novel nonvolatile memory with spin torque transfer magnetization switching: spin-ram”, Electron Devices Meeting,2005. IEDM Technical Digest. IEEE International, pp. 459-462.
S. Ikeda, J.Hayakawa, Y.M. Lee, F. Matsukura, Y. Ohno, T. Hanyu and H. Ohno, “Magnetic tunnel junctions for spintronic memories and beyond”, IEEE Trans Elec. Dev. 54, 991 (2007).
Sony
4 kb
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2007
S. Ikeda, J.Hayakawa, Y.M. Lee, F. Matsukura, Y. Ohno, T. Hanyu and H. Ohno, “Magnetic tunnel junctions for spintronic memories and beyond”, IEEE Trans Elec. Dev. 54, 991 (2007).
Y. Huai, Z. Diao, Y.Ding, A. Panchula, S. Wang, Z. Li, D. Apalkov, X. Luo, H. Nagai, A. Driskill-Smith, and E. Chen, “Spin Transfer Torque RAM (STT-RAM) Technology”, 2007 Inter. Conf. Solid State Devices and Materials, Tsukuba, 2007, pp. 742-743.
STT-RAM cell with integrated CMOS transistor. The area of a single-level STT-RAM cell can be as small as 6 F2.
Grandis, Inc.
Courtesy of Yiming Huai
115 x 180 nm2
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM 2007
S. Ikeda, J.Hayakawa, Y.M. Lee, F. Matsukura, Y. Ohno, T. Hanyu and H. Ohno, “Magnetic tunnel junctions for spintronic memories and beyond”, IEEE Trans Elec. Dev. 54, 991 (2007).
Hitachi
Courtesy of Hideo Ohno
T. Kawahara, R. Takemura, K. Miura, J. Hayakawa, S. Ikeda, Y.M. Lee, R. Sasaki, Y. Gotot, K. Ito, T. Meguro, F. Matskura, H. Takahash, H. Matsuoka and H. Ohno, “2 Mb SPRAM (Spin-Transfer Torque RAM) with bit-by-bit bi-directional current write and parallelizing-direction current read”, IEEE J Solid-State Circuits, 43, 109 (2008).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- STT-RAM
T. Kawahara, R. Takemura, K. Miura, J. Hayakawa, S. Ikeda, Y.M. Lee, R. Sasaki, Y. Gotot, K. Ito, T. Meguro, F. Matskura, H. Takahash, H. Matsuoka and H. Ohno, “2 Mb SPRAM (Spin-Transfer Torque RAM) with bit-by-bit bi-directional current write and parallelizing-direction current read”, IEEE J Solid-State Circuits, 43, 109 (2008).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAM Projections vs State-of-the-art
A.Driskill-Smith, Y. Huai, “STT-RAM – A New Spin on Universal Memory”, Future Fab, 23, 28
Hitachi, 2007
Yes
1.6 x 1.6 m TMR 100 x 50 nm2 (60)
40 ns
100 ns
> 109
40 pJ/100ns
None
1.8 V
T. Kawahara, R. Takemura, K. Miura, J. Hayakawa, S. Ikeda, Y.M. Lee, R. Sasaki, Y. Gotot, K. Ito, T. Meguro, F. Matskura, H. Takahash, H. Matsuoka and H. Ohno, “2 Mb SPRAM (Spin-Transfer Torque RAM) with bit-by-bit bi-directional current write and parallelizing-direction current read”, IEEE J Solid-State Circuits, 43, 109 (2008).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
STT-RAMProjections vs State-of-the-art
Hitachi, 2007
Yes
1.6 x 1.6 m TMR 100 x 50 nm2 (60)
40 ns
100 ns
> 109
40 pJ
T. Kawahara, R. Takemura, K. Miura, J. Hayakawa, S. Ikeda, Y.M. Lee, R. Sasaki, Y. Gotot, K. Ito, T. Meguro, F. Matskura, H. Takahash, H. Matsuoka and H. Ohno, “2 Mb SPRAM (Spin-Transfer Torque RAM) with bit-by-bit bi-directional current write and parallelizing-direction current read”, IEEE J Solid-State Circuits, 43, 109 (2008).
Toggle
MRAM (180 nm)
ToggleMRAM (90 nm)*
DRAM(90 nm)+
SRAM(90 nm)+
FLASH(90 nm)+
FLASH(32 nm)+
ST MRAM
(90 nm)*
STMRAM
(32 nm)*
cell size (m2)
1.25 0.25 0.05 1.3 0.06 0.01 0.06 0.01
Read time 35 ns 10 ns 10 ns 1.1 ns 10 - 50 ns 10 - 50 ns 10 ns 1 ns
Program time
5 ns 5 ns 10 ns 1.1 ns 0.1-100 ms 0.1-100 ms 10 ns 1 ns
Program energy/bit
150 pJ 120 pJ5 pJ
Needs refresh
5 pJ30 – 120
nJ10 nJ 0.4 pJ 0.04 pJ
Endurance > 1015 > 1015 > 1015 > 1015
> 1015 read,
> 106 write
> 1015 read,
> 106 write> 1015 >1015
Non-volatility
YES YES NO NO YES YES YES YES
* 90nm, 32nm MRAM values are projected+ These values are from the ITRS roadmap
Nick Rizzo, Freescale
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Information Requested (2/2)
• Current state-of-the-art using the provided metrics as a guide (Appendix 2 of request for white papers)CMOS integrated STT-RAM demonstrated. 2Mb
• Key scientific and technological issues remaining to accept the technology for manufacture.Lower critical currents and larger TMR ratio. Quality of the tunnel junction is critical.
• Technology roadmap outlining a 5-15 year develop path leading to manufacture in 5-10 years.Replace MRAM. Embedded memory in logic applications. Longer term – universal memory.
STT - RAM
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator
• Spin transfer torque
J. C. Slonczewski, “Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier”, Phys. Rev. B, 39 6995 (1989).
Fixed
Fre
e
-J
edm
dt
dm
dt
Slonczewski torque
Effecti
Effective field
Damping
/
ve magnetic fie d/
l
o A
B
S
B
S
p
dmm H
dt
dmm
dt
J em m
t M
J em
t Mp
P
P
dm
dtJ
• Precession• Switching• Damping
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator
30 nmPt2 nm Cu/3 nm Co/10 nm Cu/40 nmCo/80 nm Cu/
S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C. Emley, R. J. Schoelkopf, R. A. Buhrman and D. C. Ralph, “Microwave oscillations of a nanomagnet driven by a spin-polarized current”, Nature, 425,380 (2003).“
~ 0.1 nW measured
130 x 70 nm2
H
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator
30 nmPt2 nm Cu/3 nm Co/10 nm Cu/40 nmCo/80 nm Cu/
S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C. Emley, R. J. Schoelkopf, R. A. Buhrman and D. C. Ralph, “Microwave oscillations of a nanomagnet driven by a spin-polarized current”, Nature, 425,380 (2003).“
~ 0.1 nW measured
130 x 70 nm2
H
Key element: A skew magnetic field !
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator
30 nmPt2 nm Cu/3 nm Co/10 nm Cu/40 nmCo/80 nm Cu/
2 2
max
1 1 50 1
2 2 50 50DCP I RR
~ 0.1 nW measured
~ 0.2 nW estimated max.
610 Efficiency
130 x 70 nm2
H
13
0.1
2.0DC
Cu junction
R
R
I mA
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
Injection Locking
1 nm Au1 nm Cu/5 nm NiFe/4 nm Cu/20 nm CoFe/50 nmCu/5 nm Ta/
W. H. Rippard, M. R. Pufall, S. Kaka, T. J. Silva, S. E. Russek, J. A. Katine, “Injection Locking and Phase Control of Spin Transfer Nano-oscillators”, Phys. Rev. Lett., 95, 067203 (2005).
50 x 50 nm2
0.56 Tesla
~ 30 pW
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
Frequency ModulationM. R. Pufall, W. H. Rippard, S. Kaka, T. J. Silva, and S. E. Russek“Frequency modulation of spin-transfer oscillators” Appl. Phys. Lett. 86, 082506 (2005).
~ 250 pW
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
Phase LockingS. Kaka, M.R. Pufall, W.H. Rippard, T.J. Silva, S.E. Russek and J.A. Katine, “Mutual phase-locking of microwave spin torque nano-oscillators” Nature, 437, 389 (2005).
~ 2 pW
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
B=0.0T. Devoldera, A. Meftah, K. Ito, J. A. Katine, P. Crozat and C. Chappert, “Spin transfer oscillators emitting microwave in zero applied magnetic field”, J. Appl. Phys. 101, 063916 2007.
Free
Effective field, shape, material
/Slonczewski torqu
/Effective magnetic fiel
e
Damp
d
ing
o
S
B
A
B
S
dmm H
dtJ e P
m p mt M
d
J e Pm
dt
t
m
pM
m
Fixed layer
0.05
< 1.0 pW
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
Power issues?
Some measures:Cell phone – 900 MHz, 1.8GHz, ~ 500 mWWireless access points – 2.4 GHz, 5.0 GHz, ~ 25 mWAutomotive radar 24 GHz, 100 GHz ~ 10 mW
State of the art STT nano-oscillatorsExternal magnetic field, ~ nW, efficiency 10-6
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator
30 nmPt2 nm Cu/3 nm Co/10 nm Cu/40 nmCo/80 nm Cu/
2 2
max
1 1 50 1
2 2 50 50DCP I RR
13
0.1
2.0DC
Cu junction
R
R
I mA
MgO tunnel barrier
100
100
1
DC
MgO tunnel barrier
R
R
I mA
~ 1 W estimated 210Efficiency
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Transfer Torque Nano-oscillator:
Power issues?
Some measures:Cell phone – 900 MHz, 1.8GHz, ~ 500 mWWireless access points – 2.4 GHz, 5.0 GHz, ~ 25 mWAutomotive radar 24 GHz, 100 GHz ~ 10 mW
State of the art STT nano-oscillatorsExternal magnetic field, ~ nW, efficiency ~ 10-6
ProjectionMTJ based STT nano-oscillators ~ W, efficiency ~ 10-2 ?Power combining ?
But touch base with the Cornell, NIST, UVa collaboration
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Information Requested (2/2)
• Current state-of-the-art using the provided metrics as a guide (Appendix 2 of request for white papers)Nano-oscillators at the nano-picowatt level with spin valve structures, in external magnetic fields. Existence proof of approach to external magnetic field free sustained oscillation. Phase locking, frequency modulation, injection locking demonstrated.
• Key scientific and technological issues remaining to accept the technology for manufacture.Increased power. Use of magnetic tunnel junctions. Power combining.
• Technology roadmap outlining a 5-15 year develop path leading to manufacture in 5-10 years.Needs to be guided by potential applications.
STT Nano-oscillators
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
“MRAM” --- Spin Logic Device
Mark Rodwell, UC Santa BarbaraHigh
I
R
Eli Yablonovitch, UC Berkeley
source
drain
I
I
R
“transpinnor”Si (001) Substrate
Ta 5nm
Ru 50nm
Ta 5nm
NiFe 5nm
Antiferromagnetic MnIr 8nm
CoFe 2nm
Ru 0.8nm
Ferromagnetic CoFeB 3nm
MgO 1.5nm Tunnel Barrier
Ferromagnetic CoFeB 3nm
Ta 5nm
Ru 15nm
Isignal
Magnetization
Drain
Source
InsulatorCurrent Gate
BField
BField
Device Area 1?m2
Gate
Ikeda et. al., Japanese Journal of Applied Physics, Vol. 44, No 48, pp. L1442-L1445
• Current controlled• Non-volatile• “Leaky” switch, ~ 6
R
R
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Two views - Spin Logic
5μA output5μA input
500Ωor
2.275kΩ
2.275kΩor
500Ω
+V +3mV
-V -3mV
Output Power = 1.6*10-8 WTotal Power = 2.5*10-8 W
Efficiency=65%
•Problems: On/Off ratio is only about 5:1 Still takes too many Amps to switch
Eli Yablonovitch
Complementary Transpinnor logic
High
I
R
Iss
Iss
High
High
High
High
input
output
Mark Rodwell
Three state circuits• memory and logic• clocked logic• “0” static dissipation
Inverter
Iinput
Ioutput
Iss
Iss
Iinput
Ioutput
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
“MRAM” --- Spin Logic Device
Mark Rodwell, UC Santa BarbaraHigh
I
R
Eli Yablonovitch, UC Berkeley
source
drain
I
I
R
“transpinnor”Si (001) Substrate
Ta 5nm
Ru 50nm
Ta 5nm
NiFe 5nm
Antiferromagnetic MnIr 8nm
CoFe 2nm
Ru 0.8nm
Ferromagnetic CoFeB 3nm
MgO 1.5nm Tunnel Barrier
Ferromagnetic CoFeB 3nm
Ta 5nm
Ru 15nm
Isignal
Magnetization
Drain
Source
InsulatorCurrent Gate
BField
BField
Device Area 1?m2
Gate
Ikeda et. al., Japanese Journal of Applied Physics, Vol. 44, No 48, pp. L1442-L1445
• Current controlled• Non-volatile• “Leaky” switch, ~ 6
R
R
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- Spin Logic Device?
Mark Rodwell, UC Santa BarbaraHigh
I
R
Eli Yablonovitch, UC Berkeley
source
drain
I
I
R
“transpinnor”Fixed
Contact
Contact Contact
Contact
STT – “switch control”GMR – “switch”
Magnetostatically coupled free layers
Can we control GMR by Magnetostatically coupling to a STT switch ??
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- Spin Logic Device?
Fixed
Contact
Contact Contact
Contact
STT – “switch control”GMR – “switch”
Magnetostatically coupled free layers
Can we control GMR by Magnetostatically coupling to a STT switch ??
O. Ozatay,a_ N. C. Emley, P. M. Braganca, A. G. F. Garcia, G. D. Fuchs, I. N. Krivorotov,R. A. Buhrman, and D. C. Ralph, “Spin transfer by nonuniform current injection into a nanomagnet”, Appl. Phys. Lett., 88, 202502 (2006).
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- Spin Logic Device?
ISS
ISS
Input
Input
Output
Output
Current drivenClocked logicInherent memory, ISS → 0, no change in input of next stage
Iss
Iss
High
High
High
High
input
output
M. Rodwell Inverter
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
GMR and STT --- Spin Logic Device?
B Input
Input
O utput
O utput
IS S
IS S
A Input
Input
F
B Input
Input
O utput
O utput
IS S
IS S
A Input
Input
F
M. Rodwell NAND
Current controlledClocked logic3-state, nonvolatile
Cell 100F2
Energy per bit ~ 4* STT-RAMSwitching speed slower than STT-RAM
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Information Requested (2/2)
• Current state-of-the-art using the provided metrics as a guide (Appendix 2 of request for white papers)“Straw man” concepts, synergistic with STT-RAM developments
• Key scientific and technological issues remaining to accept the technology for manufacture.Demonstration of magneto-static proximity coupling of GMR device and STT switch
• Technology roadmap outlining a 5-15 year develop path leading to manufacture in 5-10 years.Premature
GMR-STT Spin logic devices
ITRS Emerging Technology Review, 12 July 2008 Contact: SJ Allen, [email protected]
Spin Torque Transfer Technology
A perspective:
STT-RAM will be developed for memory embedded in logic applications.
STT Nano-oscillators development needs to guided by potential application.
Research on potential STT Logic will be leveraged by developments in STT-RAM