Spintronic devices
P.P.Freitas
INESC-Microsistemas e Nanotecnologias/
Instituto Superior Técnico (Lisbon,PT)
and
International Iberian Nanotechnology Laboratory
(Braga, PT)
http://www.inesc-mn.pt
Frontiers on Magnetism, Benasque, February 2014
-Present markets: Data storage : PC+consumer electronics Sensors: automotive: current, power, position-linear and angular, battery cell monitoring
navigation systems-digital compassMRAM: 1st generation
-Emerging markets: NVM: STT-RAM (MRAM), M-FPGA ( integrated Sensor + CMOS)
-New sensor markets:Low power ( <mW) , low noise (nT/sqrt(Hz),medium landscape (<5mm2) integrated sensors-point of care biosensor arrays (MR sensor arrays, microfluidics, CMOS, packaging)-scanning sensor arrays (high resolution current imaging, non destructive testing)(MR, CMOS, packaging)-remote sensor networks ( hybrid RF antenna-MR sensor microsystems)
Very low noise -pT/sqrt(Hz)-integrated sensors for low frequency (1Hz) applications-MCG/MEG-hybrid MEMS-flux guide-MR sensor arrays-smart microelectrode arrays for neuroelectronics
1-Data Storage
Courtesy of Seagate
100,000
All Drives
Industry Trend up to 1991
(30% CAGR)
Industry AD Trend 1991-1996
(60% CAGR)
10,000
100
1000
1010
111980
1985 1990 20001995 2005
Are
al D
ensity (
Mbits/in
2)
Industry Drive Demo
Industry AD Trend
1996-2001 (100% CAGR)
Future Trend
Inductive
AMR
CIP Spin-Valve
2007,260 Gbit/in2)
MTJ+PR
GMR GMR heads
TMR TMR heads
2011,600 Gbit/in2)
Technology Transitions in Magnetic Recording
*After S.Iwasaki, IEEE Trans. on Magnetics (1985)
CPP Transducers
Tunneling and SV
Perpendicular Recording
B
L
dP
Perpendicular: BL 0; Hd 0
Perpendicular Recording
MTJ-MRAMCross section
MOSFET
500A
P-type Si substrate
300A
500A 3000A
STI
N+diffuision
GC
C0
M0
C1
M1
CX MX
MTJ
M2
II-SOLID STATE NON-VOLATILE MEMORIES
3 MRAM Approaches
50nm
50nm<L<150nm
<0,5ns
Iw # Jc.L2/AR
Elliptic with AR~1,5
Shape anisotropy
~1-2ns~1-2nsWriting speed
<25nm50nm Superparamagnetic
limit
25nm<L<200nmDown to L=200nm Useable range
Iw # Jh.L2Iw # 2480.(AR-1).t.8.Ms/ LWriting current
CircularElliptic with AR~1,5Bit shape
Exchange biased
storage layerShape anisotropyStabilization scheme
50nm
50nm<L<150nm
<0,5ns
Iw # Jc.L2/AR
Elliptic with AR~1,5
Shape anisotropy
~1-2ns~1-2nsWriting speed
<25nm50nm Superparamagnetic
limit
25nm<L<200nmDown to L=200nm Useable range
Iw # Jh.L2Iw # 2480.(AR-1).t.8.Ms/ LWriting current
CircularElliptic with AR~1,5Bit shape
Exchange biased
storage layerShape anisotropyStabilization scheme
FIMS writing TAS+ FIMS writing CIMS writing
IW#(AR-1).t.Ms/L
L>200nm(no toggle)
25nm
35nm<L<200nm
35nm 50nm
50nm<L<150nm
<0,5ns
Iw # Jc.L2/AR
Elliptic with AR~1,5
Shape anisotropy
~1-2ns~1-2nsWriting speed
<25nm50nm Superparamagnetic
limit
25nm<L<200nmDown to L=200nm Useable range
Iw # Jh.L2Iw # 2480.(AR-1).t.8.Ms/ LWriting current
CircularElliptic with AR~1,5Bit shape
Exchange biased
storage layerShape anisotropyStabilization scheme
50nm
50nm<L<150nm
<0,5ns
Iw # Jc.L2/AR
Elliptic with AR~1,5
Shape anisotropy
~1-2ns~1-2nsWriting speed
<25nm50nm Superparamagnetic
limit
25nm<L<200nmDown to L=200nm Useable range
Iw # Jh.L2Iw # 2480.(AR-1).t.8.Ms/ LWriting current
CircularElliptic with AR~1,5Bit shape
Exchange biased
storage layerShape anisotropyStabilization scheme
FIMS writing TAS+ FIMS writing CIMS writing
25nm
25nm<L<150nm
NEXT MRAM project ( 2000-2005)
III) Magnetoresistive Sensors in AutomobileApplications, other industrial applications
+ Navigation Systems
+ Electric Batteries Safety Systems
+ Acceleration Sensors for Airbags (MEMS+Magnetoresistive)
Advantages:• Contactless, wear-free operating
principle for angular and linear
measurement
• Large air gap
• Large permissible air gap tolerances
• Withstands extreme operating
conditions
• Full redundancy possible
• Failsafe design
• Flexible integration
• High bandwidth for measurements
in time slots of less than 100 ms
*Information from Sensitec
website
At least 15 different types of sensors using magnetoresistive
devices are already being integrated in automobiles
DNA targets
DNA probes
Substrate
Passivation
Magnetic labels
Spintronic transducer
Hybridization of DNA probe and target
IV-MagnetoResitive (MR) Biochips:diagnostics
Trends in Biotechnology, August 2004
V-Biomedical imaging applications
• Requirements:• Magnetoencephalography-fT• Magnetocardiography –pT• Low field MRI-fT
• Increase GMR/TMR sensitivity, decrease noise background
• Devices:• GMR/TMR + fluxguide hybrid sensors• MEMS + GMR/TMR hybrid sensors
MR sensors: basics1-Anisotropic Magnetoresistance
( intrinsic property)
3d moments
J
3d moments
J
M J
M J
Non spherical
3d wave functions
Different Scattering
cross sections
J.Smit, Physica 16, 612 (1951); T.R.McGuire and R.I.Potter, IEEE Trans.Magn., 11, 1018(1975);
O.Jaoul, I.A.Campbell, and A.Fert, J.Magn.Magn.Mater., 5, 23(1977); L.Berger, AIP Conf.Proc., .34,
355(1976); L.Berger, P.P.Freitas, J.D.Warner, and J.E.Schmidt, J.Appl.Phys., .64, 5459 (1988).
AMR in thin Ni80Fe20 films
0 200 400 600 800
0.5
1.0
1.5
2.0
2.5
3.0
d:N
ord
iko_3600\
CN
F_N
iFe_C
NF
_A
pril2
004.o
pj
Ta 50Å/ NiFe X/ Ta 50Å
Nordiko 3000
Ta 50Å/ NiFe X/
NiFe @ 2 sccm Xe
NiFe @ 4 sccm Xe
AM
R [
%]
NiFe nominal thickness [Å]
(Ni80Fe20)60Cr40 buffer
Ta buffer
Buffer controls grain size, mean free path and specularity
1-Control the magnetics of the thin NiFe slab:Magnetic Energy of a semi-infinite thin film (w>>h,t)
H
M
e.a.h
t
w
E/V=-o H.M + K sin2 - ½ o Hd.M
Where Hdy = -My Ny
Minimizing energy:
sin = o H Ms/ 2 Keff
Keff = K + ½ o Ms2 Ny
Ny (t/h ) ln [(h-)/ ]B.D.Cullity(1972) Introduction to Magnetic Materials, A.W, MA Theory Magnetic Recording, N.Bertram, p.172
Hd
How to make an AMR sensor?
MR
R
H
R=Rper+R cos2
Chapter 7, Theory of Magnetic Recording, N.Bertram, 1994
N.Smith, IEEE Trans.Magn., 23, 259, 1987
M
M
M
J
J
J = /4h
w
R
2- R vs H response for a single NiFe stripe
NON linear near H = 0
3-Biased Soft Adjacent Layer AMR sensor
Chapter 7, Theory of Magnetic Recording, N.Bertram, 1994
N.Smith, IEEE Trans.Magn., 23, 259, 1987
R
Hext
M
M
J
J
SAL MR
M
Hsal
+
Hdem
Linearized output
Micromagnetic simulation for SAL and MR layers
-200 -100 0 100 200
0.0
0.2
0.4
0.6
0.8
1.0 Ms(SAL)=Ms(MR)=800emu/cc
t spacer
= 100A
t SAL
=200A
t MR
=250A
j=1.2x107A/cm
2
h=4m, w>>hnorm
aliz
ed M
R
H(Oe)
AMR heads used till 1995 in HDD and still in use for tape recording
0 4h(m)
• The Spin Valve Sensor
Contact pad
Free
Pinned
W
L
h
p
f
Spacer
Exchange
Contact pad
1-C.Tsang, R.E.Fontana, T.Lin, D.E.Heim, V.S.Speriosu, B.A.Gurney, and M.L.Williams, IEEE Trans.Magn., 30, 3801 (1994).
3- B.Dieny, V.S.Speriosu, S.S.Parkin, B.A.Gurney, D.R.Wilhoit, and D.Mauri, Phys.Rev.B, 43, 1297(1991).
4- D.E.Heim, R.E.Fontana, C.Tsang, V.S.Speriosu, B.A.Gurney, and M.L.Williams, IEEE Trans.Magn.., 30, 316 (1994); P.P.Freitas,J.L.Leal, L.V.Melo, N.J.Oliveira, L.Rodrigues, and A.T.Sousa, Appl.Phys.Lett., 65, 493 (1994);
J.L.Leal, N.J.Oliveira, L.Rodrigues, A.T.Sousa, and P.P.Freitas, IEEE Trans.Magn., 30, 3031(1994).
V = ½ (R/R).I.Rsq.(W/h) <1-cos (f-p )>
GMR effect, spin dependent scattering At NM/M interfaces and in the bulk
(1986)
Spin Valve sensors-magnetic response
-900 -600 -300 0 300 600 900
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
As deposited
Hex=362 Oe
magnetic
mom
ent [m
em
u]
H [Oe]
Neel Coupling
F
P
Ta 50A
MnIr
CoFe
Cu
CoFe
NiFe
Ta
-150 -100 -50 0 50 100 150
0
2
4
6
8
10
Standard Spin Valve (#SV052)
MR = 9.6 %
Resistance = 47 ohm
Hf = 9 Oe
Hc = 3 Oe
MR
(%
)
Magnetic Field (Oe)
SV materialsBasic stack(94-97)
Specular SAF(01-)
Ta 50A
MnIr/MnPt
CoFe
Cu
CoFe
NiFe
Ta
8%<MR<10%Hc < 2OeHf < 10 OeHex > 600 Oe(MnIr)
> 1000 Oe (MnPt)
NiFeCr
MnIr/MnPt
CoFe
Cu
CoFe
NiFe
Ta
CoFe
Ru
SAF+NiFeCr(97-02)
NiFeCr
MnIr/MnPt
CoFe
Cu
CoFe
NiFe
NOL2
Ru
NOL1CoFe
Hex > 3000 Oe 14%<MR<16(20)%
10%<MR<15%
AF
MpMf
Hext
Hj
Hdem,f
Cu
J
Hf
Spin Valve Sensor: biasing
sinf = o [Hext-Hj-Hdem,p+Hf ] Ms / 2 Keff
Hdem,p
Sensor design issues
R
H
Unpatterned
MR loopPatterned
underbiased
Patterned
Properly biased
Micromagnetic simulation for SV sensor
-150 -100 -50 0 50 100 150
-1.0
-0.5
0.0
0.5
1.0 tfree
=60A
tpinn
=30A
tCu
=22A
Hf=10Oe
Hex
=600 Oe
h=2m
j=1x10 8 A/cm
2
w>>h
<sin
() fr
ee>
H(Oe)
unpatterned
0 2h(m)
Spin Valve Sensor Transfer Curve
575
580
585
590
595
600
605
610
-150 -100 -50 0 50 100 150
0
1
2
3
4
5
6
V
(mV
)
H = -15 Oe
H = 15 Oe
i = 8 mA
R = 72,0 W
MR =5,85 %
S = 0,14 %/Oe
2x6 m2
tp2d07s6
MR
(%
)
H (Oe)
Ta20Å/NiFe30Å/CoFe20Å/Cu28Å/CoFe25Å/MnIr60Å/Ta25Å
How to chose the best sensor? Noise spectrum
INESC-MN
0.1 1 1010
-17
10-16
Calculated thermal background
data
fit
SV(V
2/H
z)
Frequency (kHz)
0.1 mA sense current
1/f knee at 1 kHz
~1; ~1
R ~ 650 W
Nc ~ 1.8 E+11 noise carriers
For 1 mA sense current:
• 1/f knee at 50 kHz
• thermal noise: 0.2 nT/√Hz (linear regime)
• 30 Hz: 13 nT/√Hz (corresponds to 250 nV)
U shaped SVs, (80x2m2)
1 nT/sqrt (Hz)
Sv (thermal) = 4 KB T R
The Magnetic Tunnel Junction-Iincoherent tunneling through an amorphous barrier
ins
TMR=2P1P2/1+P1P2
CoFe 55
P=[D(F)-D(F)]/ [D(F)+D(F)]
P %
half metal 100-120 -80 -40 0 40 80 120
0
5
10
15
20
25
30
35
40
45
Al 15A, 60'' oxid.30eV O
2 beam
A=2x9m2
annealed @290ºC TMR= 40.0 %
R= 30kW
TM
R [%
]
Applied field [Oe]
Julliere´s model for incoherent tunnelingAccross amorphous barriers ( AlOx, TiOx)
Max TMR (RT)70%
(1998)
INESC-MNTunnel Junctions deposited by Ion BeamNordiko 3000 deposition system
Target assembly (shield removed)
104 x 150 mm2
Deposition source
f10 cm
Pump 2000 l/s
TurboCryo Pump CTI-8F
neutralizer Xe, Ar
Deposition
gun
Assistgun
Ar,
O2,
Ar/O2shutter
sampleV+ V-
V- V+
neutralizer
NiFe
CuM
nIr
CoFe
Ta
Al
RFsource
RFsource
O2+
O+ Ar
++
Ar+
RF plasma
33 mA Xenon beam:
Acceleration= +1450 V
Deceleration = -300V
Dep. pressure: 3.5 x10-5Torr
Table rotation: 15 rpm
Table tilt: 80º
Deposition Conditions
1nm thick barriers for read heads
CoFe
NiFe
MnIr
HfAlOx
CoFe
NiFe
Ta TiW(N)
Ta
1nm
2 3 4 5 6 7 8
0
20
40
60
80
100
120
1Torr 5mins
600AAl/Ta70A/NiFe40A/CoFe30A/X/CoFe30A/MnIr80A/Ta30A
HfOx
AlOx
(2ÅHf+(X-2)Å Al)Ox
((X-2)Å Al+2ÅHf)Ox
(2ÅZr+(x-2)ÅAl)Ox
Hf(
Oe
)
Barrier Thickness(A)
INESC-MNTunnel Junctions CharacterizationAutomatic Measurement of Transport Properties
Automatic Measurement Setup
Probe Card
36 Kelvin
Needles
KLA 3700
Probe Station
Fully Automatic Measurement of magneto-
transport properties :
- Resistance
- Magnetoresistance Transfer Curve
- Current-Voltage Characteristic
- MR Bias Voltage Dependence
- Breakdown Voltage
- Current Induced Switching
Integrated Data Analysis Software
6’’ Wafers measurement capability (2 or 4
contacts)
INESC-MNPatterned Junctions Transport Properties TMR(%)
20´´ RF power=110Wremote 0/-0V
4 sccm Ar + 40 O2
Ta 90Å/ NiFe 50Å/ MnIr 90Å/ CoFeB 40,50,60Å/ Al 9Å CoFe 30/NiFe 40/Ta 30/TiWN2
Oxidation: Top electrodeBottom electrode
60Å CoFeB 50Å CoFeB
-100 -75 -50 -25 0 25 50 75 100
0
10
20
30
40
50
TMR=47.6%
Area=2x4 m2
RxA=432 Wm2
Hf= 0 Oe
Hcfree
=22 Oe
TJ690-junction#278, annealed at 280ºC
Al600/Ta90/NiFe50/MnIr90/CoFeB50/Al9+ox/CoFe30/NiFe40/Ta30
TM
R [
%]
Field [Oe]
Hf < 2Oe, TMR > 50%, RA < 500 Ohm m2,Therm.Stab. 320 to 350C
4)-process
1) Stack dep( 10 target PVD)
1h, 330ºC, 1T
2) Magn Anneal
5 Ta
50 CuN
5 Ta
5 Ta
5 Ru
7.5 IrMn/ or 20MnPt
0.85 Ru 2.6 CoFeB
1 MgO
3 CoFeB
0.21 Ta
16 NiFe
10 Ta
30 CuN
7 Ru
2 CoFe
Free
50 CuN
Buffer
SAF
Cap
The Magnetic Tunnel Junction-IICoherent tunneling through a crystalline MgO barrier
The TMR device: process4) stack magn. characterization
Layer Ms(emu/cm3)
t(nm)
lex(nm)
Hk(Oe)
FL 1140 2.5 3.5 15
Barrier - 1 - -
RL 1140 2.5 3.5 15
Spacer - 0.85 -
PL 1070 2.3 3 15
AMF - 15 - -
Interfacial/interlayer Surface Coupling constants
(erg/cm2)
Exchange coupling between PL and AFM 0.34
Antiferromagnetic coupling for the SAF (PL/spacer/RL)
-0.53
Ferromagnetic coupling between SAF and FL
0.02
Micromagnetic Simulations:
Performed using time independent solutions of the
LLG equation.
Magnetic Parameters:
-10.0 0.0 10.0
-1.0
-0.5
0.0
0.5
1.0
Reference Layer
Free Layer
Norm
aliz
ed M
agnetic M
om
ent
H(kOe)
Unpatterned sample
Msat
(CoFeB)=1140 emu/cm3
Msat
(CoFe)=1070 emu/cm3
Hex
=3900 Oe
Hc(FL)=55 Oe
Hf(FL)=15 Oe
Pinned Layer
ExperimentalSimulation
Linear response optimization: 2nd annealing temperatureVSM plots obtained in a matrix of annealing temperature vs NiFe thickness
5 Ta / 15 Ru / 5 Ta / 15 Ru / 5 Ta / 5 Ru / 17 PtMn / 2.0 CoFe30 / 0.85 Ru / 2.6 CoFe40B20 / MgO
4x123 3kW 600sccm / 3.0 CoFe40B20 / 0.21 Ta / 8 NiFe / tMnIr / 2 Ru / 5 Ta / 10 RutMnIr=6 nm tMnIr=8 nm tMnIr=10 nm tMnIr=12 nmAnnealing
T=330 ºC
1 T, 2 hr, e. a.
T=200 ºC
1 T, 1 hr, h. a.
T=250 ºC
1 T, 1 hr, h. a.
tMnIr=14 nm tMnIr=16 nm
T=270 ºC
1 T, 1 hr, h. a.
The annealing temperature used to produce the linear response must be optimized for each stack :
notice that Hf, Hc and Hk change with the temperaure even after obtaining linear response.
The basic TMR device: process5) CIPT transfer curve characterization
-100 0 1008.9
9.0
9.1
9.2
9.3
9.4
9.5
9.6
9.7
Rsq
[Ws
q]
Field [Oe]
CIPT Transfer Curve for
a specific probe spacing
0.1 1 10 100 1000
80
100
120
140
160
180
200
220
CoFeB/MgO/CoFeB
CoFeB/CoFe/MgO/CoFe/CoFeB
TM
R (
%)
RxA (Ohm um2)
The TMR device: process6) MPW , Wafer map, die layout
INESC-MN
6 TMR
10x4 µm2
Surface
defects
Buried
defects
4 TMR
10x2 µm2
4 TMR
10x4 µm2
2 TMR
20x4 µm2
4 TMR
10x10
µm2
72 TMR
50x50
µm2
26 TMR
100x100 µm2
Process
test
area
NDT testing
Cu
Cu Cu
Ni
Mg
Mn
Ta
The TMR device-process
7) MTJ ion milling , w/wo SIMS end point detection
Multiproject Wafer Service ( 200mm and 150mm, INL and INESC MN )
MTJ stacks
deposited on
Si/SiO2 blank
wafers and
patterned with
minimum feature
sizes of 1µmm
Process extension
to 100 nm
features
available
TMR sensor: output, noise, detectivity
(V2/Hz)
(V)
(T2/ Hz)
(V/T)
For a series of N sensors
(T2/ Hz)
Full Wheatstone BridgeMagnetic sensor requirements
H =0 ; Vout=0 H ≠0
Bridge output is immune to thermal driftsVancouver
May 11th, 2012Intermag 2012 : GG-07 Slide 2/11
Final Device GeometryFull Whetstone Bridge Incorporating MTJs connected in Series
V+ V-I+ I-
Type I MTJs
R
H
Type II MTJs
R
HIrMn
CoFeRuCoFeBMgOFree Layer
Buffer
Cap
IrMn
CoFeRu
CoFeBMgOFree Layer
Buffer
Cap
CoFeRu
2-layer SAF Reference
3-layer SAF Reference
vLinear MTJ
I I
Magnetic field
3.6mm
Individual MTJ Area: 5x70 µm2
MTJ Elements in series: 110 per arm
VancouverMay 11th, 2012
Intermag 2012 : GG-07 Slide 9/11
Current in plane Transfer CurvesMTJ Stack I vs. MTJ Stack II after annealing
STEP #7 : Magnetic
Annealing
Tannealing = 330C
Dwell Time : 2h
Cool down field : 1T
TMR after Annealing ~175%
MTJ 1 MTJ 2
-100 0 1008.9
9.0
9.1
9.2
9.3
9.4
9.5
9.6
9.7
Rs
q [Ws
q]
Field [Oe]
-100 0 100
Field [Oe]
MTJ Type I MTJ Type II
RxA=10.7 kΩµm2 RxA=11.5 kΩµm2
VancouverMay 11th, 2012
Intermag 2012 : GG-07 Slide 7/11
2D MagnetometersOutput from two orthogonal bridges
V+ V-I+ I-
-314 -312 -310 -308 -306 -304 -302 -300 -298
-320
-318
-316
-314
-312
-310
-308
-306
-304
Offset Corrected
XX Field Sensor Output [mV]
Off
set
Co
rrecte
d
YY
Fie
ld S
en
so
r O
utp
ut
[mV
]
YY
Fie
ld S
en
so
r O
utp
ut
[mV
]
XX Field Sensor Output [mV]
VBridge
=3.3V
-8 -6 -4 -2 0 2 4 6 8
-8
-6
-4
-2
0
2
4
6
8V
+V
-I+
I-
XX Component
SensorYY Component
Sensor
Sensor output during a 360○ rotation
13.3 mV/V/Oe sensitivity 0.31 Oe field
VancouverMay 11th, 2012
Intermag 2012 : GG-07 Slide 11/11
ENIAC-JTI
NDT Testing with TMR sensors
INESC-MN
Aluminum Mock-up with a width of 100 µm
and a depth ranging of 0.2, 0.5 and 1 mm
In collaboration with INESC ID
FP7-IMAGIC
-100 -80 -60 -40 -20 0 20 40 60 80 100
3000
4000
5000
6000
7000
8000
9000
Linear range : -29 Oe to 20 Oe
Hc = 0.55 Oe
Hf= 5.7 Oe
Re
sis
tan
ce
[W
]
H [Oe]
TMR=174.5%
RxA= 30.6 kWm2
Series of 1102 MTJs with
100x100m2
200mm wafer processed at INL
TJ933 – Si / Al2O3 (100nm) / [5 Ta / 25 CuN]x6 / 5 Ta / 5 Ru / 20 IrMn / 2 CoFe30 / 0.85 Ru / 2.6
CoFe40B20 / MgO 2x41 / 2 CoFe40B20 / 0.21 Ta / 4 NiFe / 0.20 Ru / 6 IrMn / 2 Ru / 5 Ta / 10 Ru
(Ta/Cu) x n
Buffer minimizes
Interconnect
resistance
contribution
MINIMIZING INTERCONNECT RESISTANCE IN LARGE MTJ SERIES, stack 4
Previous results – Buried defects
INESC-MN
INESC-MN
Internal TMR probe tests at INESC MN
fbias=999kHzI s = 100 µA 0-p
f excitation = 1000 kHzI exc = 1 A 0-p
f meas =1 kHz
INESC-MN
Friction Stir Welding detection
WeldingDefect
400 µm
TMR - Single ended TMR - differential
Top view(scanning side)
Bottom view(Welding side)
Cross section
Signal (µV) Signal (µV)
1mm/s
Scanning probescurrent imaging in Ics
100 1000 10000 100000
10
100
No
ise
(n
T/H
z0
.5)
Frequency (Hz)
INESC MN-NEOCERA
2x2 m2
SPIN, 2011
TMR sensor linearization strategies2: thin CoFeB ( out of plane)
INESC-MNSlide 5
glass/Ta 5/Ru 18 /Ta 3/PtMn 18/CoFe 2.2/ Ru 0.9/
CoFeB3/MgO1.35/CoFeB 1.55 / Ru 5/Ta 5
P. Wiśniowski et al, JAP 103,07A910 (2008)
P. Wiśniowski et al, IEEE Trans. Mag.,44(11), 2551-2553 (2008)
Thick Free layer
TMR @ 20°C 76%
Sensitivity @ 0 Oe &20°C
250 V/V/Tesla
Linear range @20°C [-5 Oe; 5 Oe]
Voltage Noise @ 10 kHz & 20°C
700 nV/√Hz(for single TMR)
Voltage Noise @ 10 MHz & 20°C
70 nV/√Hz(for single TMR)
Field Noise @ 10 kHz & 20°C
6 nT/√Hz(for single TMR)
Field Noise @ 10 MHz & 20°C
0.6 nT/√Hz(for single TMR)
With permission from M.Pannetier, C.Fermon
Reaching pT detectivity with MR sensors
With permission from M.Pannetier, C.Fermon
Hybrid SC-SV devices, measured at 4K
Hybrid MTJ+flux guide structures: towards pT detection at RT and low freq.
500 m
10 m
Goal: increase volume of free layer-reduce magnetic 1/f noise
increase junction area-decrease barrier 1/f noise
increase sensitivity: flux guides + MgO MTJ
MTJ pillarFlux guide tip
Top contact
Long.
Permanent
Magnet biasing
Biomagsens Mid Term Review INESC-MN
Noise characteristics
0 20 40 60 80 1000
50
100
150
200
VThermal
+VShot
= 0.42 nV/Hz0.5
SRS SIM910 Amplifier,40 dB
Span 100Hz; RBW 1Hz; AVG 1000
=3.2 E-9 m
2
51 pT @ 30 Hz
97 pT @ 10 Hz
Wafer#1650 (Singulus), RxA 150 Wm2
PME2, Sensor# 55
A[m2] = 676(26x26) ; R
Low= 1.36 W
Ro = 2.1 W; TMR = 97%; S = 72 %/Oe
Field ResolutionS
v[p
T/H
z0.5]
f[Hz]
Room
Temperature
External
Long Bias 35 Oe
IBias [A]
0.01
0.1
Biomagsens Mid Term Review INESC-MN
Appl. Phys.Lett., 91, 102504, August 2007
(1pT at 500 kHz)
Need reduce 1/f mag and
white mag noise
INL approach to picoTesla field detectionLarge Arrays of linear MTJs integrating large area MTJs
Detection of very weak magnetic fields at INL :
Array of 1102 MTJs connected in series with an individual area of 100x100 m2
Direct detection of weak magnetic fields obtained WITHOUT magnetic shielding.
Total Area : 4x6 mm2
-400 -300 -200 -100 0 100 200 300 400
3000
4000
5000
6000
7000
8000
9000
10000
Resis
tan
ce [W
]
Measured Applied Magnetic Field [Oe]
TMR=174.5%
RxA= 30.6 kWm2
R [1 MTJ] =3.06 W
Linear range : [-29 Oe : 20 Oe][H=0] :
dR/dH= 126.2 W/Oe
INESC-MN’s static, multiplexed MR biochip8 mm 40 µm
Sensor
Spotted probe
ftmolar sensitivity (DNA chip)multiplexed analysis
CMOS, microfluidics, sensors
10-16
10-15
10-14
10-13
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
No target DNA
V
bin
din
g
ac
/ V
senso
r
ac
DNA concentration (M)
Passive hybridization
Assisted hybridization
Non-Complementary
target DNA*
Tech review, Lab On Chip 2012
Snip2Chip Lisbon meeting INESC-MN
1-d) Spotting biological targets on the biosensing platform
1 µM Oligo solution, Cy5 labeled200 pL droplets
Gesim spotter
Spotting site
Disposable biochip
Blood finger-prick
Sample preparation step
separation of plasma from blood cells
Plasma injected in the detection chip
Measurement of the chip
Protein/DNA Biochip
Cell free DNA detection in blood
As cancer biomarker
ENVIRONMENT MONITORING, SECURITY AND FOOD QUALITY CONTROL
Elisabete Fernandes, PhD StudentContact E-mail: [email protected]
Protein A MNPs 250 nm covered
with anti-Salmonella antibody
Salmonella Enteritidis
Salmonella Bacterio(phage) PVP-SE1
-50
0
50
100
150
200
250
0 10 20 30 40 50 60 70
Time (min)
Δ V
(μ
Vrm
s)
"Reference Sensor"
"Negative Sensor"
"Positive Sensor"
The signal obtained…
Specific bacteriophage for Salmonella enteritidis
Affinity of the specific phage was about20 times higher (average absolute valueof 100 µV against 5 µV).
No bacteriophage
Unspecific bacteriophage
Also used for protein and immuno assays
Detecting labelled cells in flow
Cell detection – Kg1a cells/CTCs
cell=5-10m
Cells marked with 50nm
FeOx particles
Lab on Chip ( 2011)
NANODEM FP7 (2012-2015)
Stimulation electrode
Recording electrode
Rat hippocampus
Synaptic current monitoring with highSpatial resolution ( with A.Sebastiao, IMM, V.Santos, ICVS)
INESC MN and IMM
MAGNETRODES, FP7 (2013-2016)
Si Needles with MR sensors or planar electrode array of MR sensors
INESC – MN
400µm Oxide Layer
Substract
SV SV SVSV
Mice Brain Slice
Stimulation Electrode Recording
ElectrodeMagnetic
field
Action Potential Currents
0.4µm
Mic
ron
eed
le s
en
sor
arr
ayP
lan
ar s
en
sor
arra
y
Probe design for in-vitro applications
1mm width
0.5 mm width
1) Shaft angle 18º
2) Thickness < 100 µm
3) Length ~ 1 cm
18º
• Optimized SV and MTJ sensors
• Probe specifications:
FP7 MAGNETRODES (2013-2015)Probe desigb for in-vivo applications
1mm width 0.5 mm width175 μm width 100 μm width
Silicon probes
INESC-MN
– Probe Tip Area -1000x1000 µm2
– 140 Magnetic Tunnel Junction sensors
– each sensor – 50x50 µm2
Flexible Probes(polyimide)
Measurement of neuronal activity using magnetoresistive sensor integrated in Micromachined Needles
Results – MTJ response
INESC – MN
The MTJ sensor readout:
- 20μV amplitude
- 20uV amplitude signal corresponds to a magnetic field of about 3μT.
- Type of signal expected
1.56 1.58 1.60 1.62 1.64 1.66 1.68 1.70-60
-45
-30
-15
0
15
30
45
60
OutP
ut
Voltage (
uV
)
Time (s)
Signal
Impulse
In Vivo - Spinal Cord
VI: New spintronic Nanodevices ( STT-RAM, Nano Osc., ...)
Applications
Jie Yang et al. IEEE Trans. Magn., 46, NO. 6 (2010)
Spin Transfer Torque -MRAMs Spin Transfer Torque based NanoOscilators Magnetoresistive Nanosensors with improved spatial resolution
Memory Elements High Frequency Generators Field Nanosensors
MR element with TE and BE -100 -50 0 50 100
0
1
2
3
4
5
6
7
50 nm
100 nm
200 nm
500 nm
800 nm
1000 nm
Mag
neto
resi
stan
ce (
%)
H(Oe)
2000 nm
heigth
L=8 m
distance btw ctcs = 4 m
Spin Valve Sensor
Cross section
MOSFET
500A
P-type Si substrate
300A
500A 3000A
STI
N+diffuision
GC
C0
M0
C1
M1
CX MX
MTJ
M2
Micromagnetic Simulations
2
-10.0 0.0 10.0 20.0
-1.0
-0.5
0.0
0.5
1.0
-10.0 0.0 10.0
-1.0
-0.5
0.0
0.5
1.0
ma
gn
etic m
om
en
t / A
rea
(m
em
u/c
m2)
H(kOe)
Micromagnetic Simulation
Jex
= 0.34 erg/cm2
JSAF
= -0.53 erg/cm2
Jf = 0.02 erg/cm
2
Ms(CoFeB) =1070 emu/cm
3
Ms(CoFe)=1200 emu/cm
3
magnetic moment/Area
H(kOe)
VSM curve
Unpatterned
(memu/cm2)
HkFL
RL
PL
Hap
FreeLayer
Dot = 50 nm
50 nm
-1500 -1000 -500 0 500 1000 1500
-3x104
-2x104
-1x104
0
1x104
2x104
20 nm30 nm
40 nm
50 nm
60 nm
70 nm
80 nm
Mag
netic
Mom
ent (
T.n
m3)
Applied Field (Oe)
90 nm
Free-Layer behavior
Accurately choose the properties/dimensions of nanostructures to fabricate in accordance with the envisaged application
Process for STT Nano-oscilators: Simulations
INESC-MN
INESC MN
Clean room class 1000
Obrigado!
INL
MR DEVICE MICROFABRICATION PROCES Current-perpendicular-to-plane (CPP) device fabrication
Microfabrication process
Optical lithography - DWL
Critical Step #1 : Ion Milling of a NanoPillarEtch Stop Point Detection
Ion Gun
TiW Ru Ta
IrMn
NiFeMgO
IrMn
Key Parameters :
RF Power : 190WV+: +150VV- : -1500VI+ : 184mAI- : -43mA
Ar Flow : 45 scmmP=3.21x10-4 TorrNeutralizes : 2 x [90mA; 4 sccm ]Rotation : 30 rpm
BragaJune 6th, 2012
Slide 4/15
Up to 70,000 sensor devices in a 200mm diameter wafer
