2.76/2.760 Multiscale Systems Design & Manufacturing · 2.76/2.760 Multiscale Systems Design &...

Sang-Gook Kim, MIT

2.76/2.760 Multiscale Systems Design & Manufacturing

Fall 2004

Piezoelectricity-2

Sang-Gook Kim, MIT

Spontaneous polarization

Ba2+

O2-

Ti4+

0.1A

0.06A

0.03A

: Polarization per unit cell volume) / a2cnonpolar()polar( PPP −=∆

HW1: Calculate the magnitude of spontaneousPolarization. a=3.992 A, c=4.036a1e=1.602x10-19 C

BaTiO3Dipole moment=Σ charge x position shift

= 8(2e/8)(0.06 x 10-10 m) + 4e(0.1 x 10-10 m)+ 2(-2e/2)(-0.03 x 10-10 m)

=0.9292 x 10-29C mVolume=a x a x c=64.3 x 10-30 m3

Spontaneous Polarization = 0.145 C/ m2

c

aFigure by MIT OCW.

Sang-Gook Kim, MIT

d31 vs d33

PZT layer

ZrO2 layer

+ - + - + - +

Membrane layer

Interdigitated Electrode

P

HW2: Compare generated voltages V31 (from d31mode),V33 (d33mode). Both havesame cantilever dimension, butdifferent electrodes.

Assume, g33=2g31tpzt=o.5 µd=5 µlength=100 µ, width=50 µYoung’s modulus of the beam=65 Gpa, max strain=0.1%

d33=200 pC/nK=1000

Sang-Gook Kim, MIT

Principles of piezoelectric

Electric field(E)

Strain(S) Entropy

Stress(T) Temperature

g

-e

-eg

d

-h

d

-h sc

Dielectric Displacement(D)

εβ

Thermo-elastic effect

Electro-thermal effectPiez

oelec

tric e

ffect

Sang-Gook Kim, MIT

Piezoelectricity

• D: dielectric displacement, electric flux density/unit area• T: stress, S: strain, E: electric field• d: Piezoelectric constant, [Coulomb/Newton]

Direct effect

dTQ/AD ==Converse effect

dES =

-gTE =

od/Kd/g εε ==

Sang-Gook Kim, MIT

∆T/T = d33 · E

Longitudinal (d33) Transverse (d31)

ΔL/L = d31 · E

Electrical energy Mechanical energyActuator

Shear (d15)

Shear strain = d15 E

PE

Piezoelectric Charge Constants

Diagram removed for copyright reasons.Source: Piezo Systems, Inc.

"Introduction to Piezo Transducers." http://www.piezo.com/bendedu.html http://www.piezo.com/bendedu.html

"Introduction to Piezo Transducers." Source: Piezo Systems, Inc.Diagram removed for copyright reasons.

Sang-Gook Kim, MIT

Coarse Positioning

• Screw• Louse• Beetle

Courtesy of Friedrich-Alexander University. Used with permission.Source: "Scanning Tunneling Microscopy" http://www.fkp.uni-erlangen.de/methoden/stmtutor/stmtech.html

Sang-Gook Kim, MIT

STM tip scanning

• Tripod

hLVdx 31=∆

hLd

Vx

31=∆

PZT-5Hd31: -2.74 Angstrom/Vd33: 5.93 A/VE: 6.1 1010N/m2Tc: 195 CQ: 65ρ: 7.5g/cm3C: 2.8 km/sec

For L=20mm, h=2mm, PZT-5H

Resonant frequency=?

?=∆Vx


Sang-Gook Kim, MIT

Bimorph bender

+V h/2

L2

2

31

31

2

1

1

311

3

6:

3

)(0

)(2/

1

hLVdz

Vdhradius

h

dzzzM

zzh

VEd

=∆

=

=

==

−=

±=

∫

ρ

σα

σ

ασσ

σ


Sang-Gook Kim, MIT

Tube scanner

• Piezo Tube with ¼ electrodes

+v

-V

y,θ

L

δy


Sang-Gook Kim, MIT

Tube scanner, deflection

DhVLdy

VdDhR

πδ

π

231

31

22

24

=

=

Curvature

Resonant frequency 40KHz (z), 8 KHz(x,y),For a tube of 12.7mm L, 6.35 mm diameter, 0.51mm thick

Sang-Gook Kim, MIT

Design of a Z-axis scanner

1350.1326215972 x 3 x 9P-882.10

Resonant Frequency [kHz]

Electrical Capacitance [µF] (±20%)

Stiffness [N/µm]

Blocking Force [N @ 120 V]

Max. Displacement [µm @ 120 V] (±10%)

Nominal Displacement [µm @ 100 V] (±10%)

Dimensions A x B x L [mm]

Ordering Number*

Component schematic removed for copyright reasons.Physik Instrumente Z-positioner P-882.10,

in http://www.pi-usa.us/pdf/2004_PICatLowRes_www.pdf, page 1-45.

Sang-Gook Kim, MIT

Case 1: Piezoelectric micro-actuators

Positives1. Low power and

voltage for thin films

2. High force3. Compact

Modified from P. Krulevitchet al,"Thin Film Shape Memory Alloy Microactuators,“ JMEMS Vol. 5, No. 4. 1996 pp 270-282.

1 10

Cycling Frequency (Hz)

Wor

k / V

olum

e (J

/m3 )

102102

103

104

105

106

107 SMASolid-liquid

Thermo-pneumatic

Thermal expansion

Muscle

µ-bubble

PZT

PZT

108

103 104 105 106 107

Thin film

Electro-static

Electro-magnetic

Figure by MIT OCW

Sang-Gook Kim, MIT

Leveraged Amplification

h1

h3

h2

g

l1

h

L1

h

L0

US Patent pending, N. Conway, S. KimSang-Gook Kim, MIT

Bow Strain Amplifier

Sang-Gook Kim, MIT

Amplification depends on 2 factors

( )⎟⎠⎞

⎜⎝⎛ +−=

−−

=∆∆

000

21cot

coscossinsin θθ

θθθθ

xy

θ0 = initial angle

y

x

θ

Figure by MIT OCW.

Sang-Gook Kim, MIT

Small angles yield enormous amplification

5 10 15 20 25 30 35 40 45-60

-50

-40

-30

-20

-10

0

θ (deg)

∆y/∆x

amplification

5 10 15 20 25 30 35 40 45-60

-50

-40

-30

-20

-10

0

θ (deg)

∆y/∆x θ0 = 1º

Sang-Gook Kim, MIT

Bottom

Piezoelectric Amplifiers

Fixed substrate

Released

End effector

PZTTop

MIT Bow-actuator Nick Conway, MS 2003

4-bar linkage design

Sang-Gook Kim, MIT

Flexural pivots enable a parallel guiding linkage in a high aspect ratio structure.

LYIk ≈θ

Sang-Gook Kim, MIT

Process Flow 1- 4 mask process1

2

3

Deposit oxide (SiO2) layer on Si substrate

Deposit and pattern Pt/Ti bottom electrode layer (#1)

Spin-on PZT

Sang-Gook Kim, MIT

Process Flow 24

6

5

Pattern then anneal PZT (#2)

Deposit top electrode (platinum) (#3)

Spin-on SU-8 (30 µm) and cure, expose, and develop (#4)

Sang-Gook Kim, MIT

Process Flow 37

8

RIE oxide

XeF2 etch away Si to release actuator

Sang-Gook Kim, MIT

Finished

Note: SU-8 non-conducting.

Nick Conway, Micronanosystems Laboratory, MITSang-Gook Kim, MIT

MEMS-Strain-Amplifier

500 µ

Sang-Gook Kim, MIT

Arrayed configurations –Cellular analog digital actuation

Sang-Gook Kim, MIT

Case: Piezoelectric Micro Power Generator

PZT

ZrO2

+ - + - + - +

membrane

Inter-digitated Electrode

E3

MIT Media Lab, Shoe Power MIT EECS, ChandrakasanEnergy Amplifier

Sang-Gook Kim, MIT

Comparison of Energy Scavenging

Shad Roundy, Paul K. Wright, Jan Rabaey, Computer Communications xx(2003) 1‐14

28 µW/cm3 (280 µW/cm3 one year life)Fuel cells (methanol)

33 µW/cm3 (330 µW/cm3 one year life)Hydrocarbon fuel (micro heat engine)

0 µW/cm3 (7 µW/cm3 one year life)Batteries (rechargeable)

3.5 µW/cm3 (45 µW/cm3 one year life)Batteries (non-rechargeable)

15 µW/cm3(at 10 oC gradient)Temperature gradient

0.003 µW/cm3(at 75 dB)Acoustic noise

50 µW/cm3Vibrations (electrostatic)

250 µW/cm3Vibrations (piezoelectric)

6 µW/cm3Solar (indoor)

15,000 µW/cm3Solar (outdoor)

Power Density for 10 YearsEnergy Source

Sang-Gook Kim, MIT

VibrationAcoustic Source

Energy Output

High deformationin piezoelectric

Electricalsignal

Energy Harvesting Concept with Piezoelectricity

mechanicalresonance

Vibration/acousticamplitude

Membraneamplitude

charge/voltage

DC outputvoltage

piezoelectricity rectifying

• Energy conversion efficiency (ηp)ηp = generated energy/input energy

≈ 65 to 78 %• No voltage source needed • Open circuit voltage: 3~15V

JMM, 14, 717

Sang-Gook Kim, MIT

V33 = 2L / tpzt • V31 ≅ 20 • V31 ≅ 3 Vg33>2g31L~10tpzt

Piezoelectrics

Sang-Gook Kim, MIT

• High strain: cantilever beam, proof mass• High open-circuit voltage:

d33 interdigitated electrodes

b

t

L

Device Design

Sang-Gook Kim, MIT

Device Modeling

i2L33

m zmL4t3

bVdkkbm =−δ+δ+δ

ioomo zm)EMC(kzzbzm −+−−=

Governing equation for seismic excitation

( )δ−ε

−== 233

33s k1

YbdbEV

Open Circuit Voltage of PMPG

Y: Young’s modulusδ: straind: piezoelectric coeff.K33: coupling constant

Sang-Gook Kim, MIT

(a) Films deposition (CVD, spinning)

(b) Top electrode deposition (e-beam)and then lift-off

(c) Films patterning (RIE)

(d) Proof mass (SU-8, spinning)

Device Fabrication

PZT (Pb(Zr,Ti)O3)ZrO2

Membrane

Si

Interdigitated Electrode (Ti/Pt)Proof mass

Sang-Gook Kim, MIT

(e) Cantilever release (XeF2 etcher)

(f) Packaging & PZT poling

Device Fabrication (II)

Sang-Gook Kim, MIT

XRD peaks of PZT film

Characterization of PZT films

500 nm

uniform grain sizes

-100 -50 0 50 100-80

-60

-40

-20

0

20

40

60

80

After poling

Pola

rizat

ion

(µC

/cm

2 )

Applied voltage (V)

Before poling

20 30 40 50 60

ZrO

2 (111

) PZT

(011

)

Pt(2

00)

Pt(1

11)

PZT

(210

)

PZT

(002

)

PZT(

211)

PZT

(111

)

ZrO

2 (200

)

PZT

(001

)

Inte

nsity

(A.U

.)

2θ

1 10 100

0.0

0.4

0.8

1.2

600

800

1000

1200

dielectric constant dielectric loss

frequency (kHz)

typical thin-film

PZT dielectric

Sang-Gook Kim, MIT

PZT characterization

High performance PZT thin film

-d33=200 pC/N, d31=-100 pC/N,

-ε=1200,

-tanδ=0.02 at 15 kHz

Sang-Gook Kim, MIT

Cantilever Bow Control

ZrO2(0.05um)/thermal oxide(0.4um)

ZrO2(0.05um)/PECVD oxide(0.4 um)

ZrO2(0.05um)/PECVD oxide(0.1um)/LPCVD nitride(0.4um)

(A) (B) (C)TowardsTensile stress

TowardsHigh elastic modulus

Photos removed for copyright reasons.Source: Jeon, Y.B., R. Sood, J.H. Joeng and S.G. Kim. “Piezoelectric Micro Power Generator for

Energy Harvesting.” Sensors and Actuators A: Physical, accepted for publication, 2005.

Sang-Gook Kim, MIT

50 100 150 200 250 300 350

-2000

0

2000

4000

6000

8000

-200 MPa -100 MPa 0 MPa 100 MPa 200 MPa

Can

tilev

er C

urva

ture

[1/m

]

Elastic Modulus of Bottom Layer [GPa]

(A)

(B) (C)

Cantilever Beam Structure

PZT

ZrO2SiO2

Variable Membrane

Cantilever Bow Control (II)

Sang-Gook Kim, MIT

Top view of PMPG SEM image of PMPG

Multiple cantilever device SEM image of PMPG

Fabricated PMPG devices

Photos removed for copyright reasons.Source: Jeon, Y.B., R. Sood, J.H. Joeng and S.G. Kim. “Piezoelectric Micro Power Generator for

Energy Harvesting.” Sensors and Actuators A: Physical, accepted for publication, 2005.

Sang-Gook Kim, MIT

PMPG

Laser Vibrometer

Laser beam

OPTICS TABLEPiezoelectric

Shaker

X-Z-θ translation

Charge Amplifier

Voltage Amplifier:

Set-up for measurement

Sang-Gook Kim, MIT

0 25 50 75 100 125 150 175 200

0

1

2

3

4

5

Tip

Dis

plac

emen

t [µm

]

Frequency [kHz]

48.5kHz

21.9kHz

13.9kHz1st mode at 13.9 kHz

2nd mode at 21.9 kHz

3rd mode at 48.5 kHz

Resonant Response of Cantilever Tip

Sang-Gook Kim, MIT

• First mode of resonance at 13.9 kHz with 14 nm amplitude• Rectifying the AC signal, then store the charge• Variation of load resistance

Power Generation

2.28V

Load

vol

tage

(V

c)

Time (sec)

0.4µAS

ourc

e cu

rren

t (µ

V)

Time (sec)

Schottky diodes: smallest forward voltage drop10 nF mylar cap: low leakage current

Sang-Gook Kim, MIT

Measurement of generated power

0 2 4 6 8 10

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Gen

erat

ed V

olta

ge (V

c,V)

Resistive Load (RL,M-Ohms)

at 13.9kHz0 2 4 6 8 10

0.0

0.2

0.4

0.6

0.8

1.0

Pow

er D

eliv

ered

To

Load

(PL,

µW)

Resistive Load (RL, ΜΩ )

at 13.9kHz

3V 1µW

Generated voltage (Vc) Generated power (PL)

Proof massInterdigitated electrode

Si

ZrO2

PZT

Y. Jeon, R. Sood, and S.G. Kim, Hilton Head Conference 2004

Sang-Gook Kim, MIT

Infinite60,000 cycles(charge/discharge)

10 yearsStorage Conditions

-20~80oC-50~180oC-20~60oCOperating Temperature

0.74 mWh/cm20.8 mWh/cm2637 Wh/LEnergy Density

ExcellentNonhermeticNonhermeticHermeticity

MEMS Packaging

Thin FilmSpiralInternal Construction

3V4 V3.1 VNominal OCV

PMPGLi/LiCoO2Li/MnO2Characteristic

Summary

• Energy conversion efficiency (ηp)ηp = generated energy/input energy

≈ 65 to 78 %• No voltage source needed • Open circuit voltage: 3V

Sang-Gook Kim, MIT

Power depends on

• Resonant Frequency• Internal Capacitance and Resistance• External Capacitance and Load Resistance• Mechanical damping• Membrane structure• Electrode shape

•Bow control?•Multi-cantilever Multiple bridges?

New Design for Efficient Power Harvesting

Sang-Gook Kim, MIT

In progress,

• High resonant frequency products– Bridge Structures vs. Cantilevers– Smart bearings

• Low resonant frequency structures– Scavengers

• Monolithic Device Design– Mechanical Rectifiers

Sang-Gook Kim, MIT

Concept prove

New Design & PMPG integration

Design and fabrication

On chip RFID with PMPG and Sensor

PN

GeneratorRF circuit RectifierStorage

PMPG

RF transmitter+

Sensor+

Self-supportive Wireless Sensors

Sang-Gook Kim, MIT

Wireless Sensing Applications

Network data transferNetwork data transfer

PMPGRF transmitter

+

sensor+

Reader

RF transmitter with pressure sensor and power generator in tires

Dashboard display with RF receiver

Self-supportive Sensors

Industrial process(i.e. pipeline)

Vehicle

Industrial process(i.e. pipeline)

Sang-Gook Kim, MIT

Can we avoid disasters?

Belgian gas pipe blast kills 15, destroys plants

PICTURE shows the cut gas pipeline which exploded at an industrial estate in Ghislenghien, southern Belgium, July 30. -AFPpix.

GHISLENGHIEN (Belgium) July 30 - A huge blast on a leaking gas pipeline in Belgium on Friday sent giant fireballs in the air and catapulted bodies hundreds of metres in the biggest industrial disaster in the country's recent history.At least 15 people were killed and more than 100 injured when the explosion ripped through the underground pipeline in the industrial zone of Ghislenghien, near the town of Ath, 40 km (25 miles) southwest of Brussels.

Photo removed for copyright reasons

2.76/2.760 Multiscale Systems Design & Manufacturing · 2.76/2.760 Multiscale Systems Design &...

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