EE C245 – ME C218 Introduction to MEMS Design Fall 2008 · PDF fileEE C245 – ME C218 Introduction to MEMS Design ... Benefits of Scaling. ... Benefits of Size Reduction: MEMS

EE C245 – ME C218Introduction to MEMS Design

Fall 2008Fall 2008

Prof Clark T C NguyenProf. Clark T.-C. Nguyen

Dept of Electrical Engineering & Computer SciencesDept. of Electrical Engineering & Computer SciencesUniversity of California at Berkeley

Berkeley, CA 94720y

L t 2 B fit f S li

EE C245: Introduction to MEMS Design Lecture 2 C. Nguyen 9/2/08 1

Lecture 2: Benefits of Scaling

Lecture Outline

• Reading: Senturia, Chapter 1g p• Lecture Topics:

Benefits of MiniaturizationExamplesExamples

GHz micromechanical resonatorsChip-scale atomic clockpMicro gas chromatograph


Technology Trend and Roadmap for MEMSs

108

109

DistributedStructural Digital Micromirror

Pentium 4

ompu

te

sist

ors

106

107Structural

ControlTerabit/cm2

Data Storage

DisplaysADXL-50

Digital MicromirrorDevice (DMD)CPU’s

Phased Array

bilit

y to

co

of T

rans

104

105

10

Adaptive

Integrated FluidicSystems

InertialNavigationOn a Chip

Displays

W

OMM 32x32

i-STAT 1Caliper

Phased-ArrayAntenna

crea

sing

ab

mbe

r o

2

103

104 AdaptiveOptics

Optical Switches& Aligners

Weapons,Safing, Arming,

and FusingADXL-278

Future MEMSIntegration Levels

Enabled Applications

Caliper

inc

Num

101

102

ADXL-78ADXRS

Number of Mechanical Components

100

100 101 102 103 104 105 106 107 108 109Majority of

Early MEMS


increasing ability to sense and actNumber of Mechanical Componentsy

Devices(mostly sensors)

Example: Micromechanical Accelerometer

• The MEMS Advantage:>30X size reduction for accelerometer mechanical element m

Tiny mass means small output need

accelerometer mechanical elementallows integration with IC’s

Basic Operation Principle

400

μmintegrated transistor circuits to compensate

xo

Basic Operation Principle

maFx i =∝

xSpring

Displacement

a Inertial Force

Spring

A l ti

Proof Mass


AccelerationAnalog Devices ADXL 78


108

109


Pentium 4

DisplaysPhased Arrayompu

te

sist

ors

106

107Structural

ControlTerabit/cm2

Data StorageADXL-50


Analog Devices ADXRS

OMM 8x8 OpticalCross-Connect Switch

Adv.: faster switching, lowDisplaysPhased-ArrayAntenna

bilit

y to

co

of T

rans

104

105

10

Adaptive



W

OMM 32x32

i-STAT 1Caliper

gIntegrated Gyroscope

Adv.: small size

Adv.: faster switching, low loss, larger networks

crea

sing

ab

mbe

r o

2

103

104 AdaptiveOptics



and FusingADXL-278


Enabled Applications

Caliper

inc

Num

101

102

ADXL-78ADXRSCaliper Microfluidic Chip

Ad l l f tTI Digital Micromirror Device


100

100 101 102 103 104 105 106 107 108 109Majority of

Early MEMS

Adv.: low loss, fast switching, high fill factor



Devices(mostly sensors)Adv.: small size, small

sample, fast analysis speed


108

109


Pentium 4

ompu

te

sist

ors

106

107Structural

ControlTerabit/cm2

Data StorageADXL-50


umpt

ion

DisplaysPhased Array

bilit

y to

co

of T

rans

104

105

10

Adaptive



W

OMM 32x32

ower

con

s

i-STAT 1Caliper

DisplaysPhased-ArrayAntenna

crea

sing

ab

mbe

r o

2

103

104 AdaptiveOptics



and FusingADXL-278


Enabled Applicationsreas

ing

po Caliper

inc

Num

101

102

ADXL-78incr ADXRS

Lucrative Ultra-Low Power Territory(e.g, mechanically powered devices)


100

100 101 102 103 104 105 106 107 108 109Majority of

Early MEMS



Devices(mostly sensors)

Benefits of Size Reduction: MEMS• Benefits of size reduction clear for IC’s in elect. domain

size reduction speed, low power, complexity, economy•MEMS: enables a similar concept but MEMS extends the benefits of size reduction

beyond the electrical domain

•MEMS: enables a similar concept, but …

beyond the electrical domain

Performance enhancements for applicationdomains beyond those satisfied by electronics

in the same general categories in the same general categories Speed

P C nsumpti nFrequency , Thermal Time Const. A t ti n En H tin P Power Consumption

ComplexityE

Actuation Energy , Heating Power Integration Density , Functionality B t h F b P t ( f k i )


Economy Batch Fab. Pot. (esp. for packaging)Robustness g-Force Resilience

Vibrating RF MEMSVibrating RF MEMS


Basic Concept: Scaling Guitar Strings h l Guitar String

e

μMechanical Resonatorm

plitu

de

Low Q

High Q

Vib.

Am

Vibrating “A”String (110 Hz)

110 Hz Freq.Performance:

L =40 8μm[Bannon 1996]

String (110 Hz)

Stiffnessfo=8.5MHzQvac =8,000

Qair ~50

Lr 40.8μmmr ~ 10-13 kg

Wr=8μm, hr=2μmd=1000Å, VP=5V

ro

kf 1=

Freq. Equation:air , P

Press.=70mTorr


Guitar ro m

fπ2

Freq. Mass

Frequency of a Stretched Wire


Frequency of a Clamped-Clamped Beam


Frequency of a Clamped-Clamped Beam


Basic Concept: Scaling Guitar Strings h l Guitar String

e

μMechanical Resonatorm

plitu

de

Low Q

High Q

Vib.

Am

Vibrating “A”String (110 Hz)

110 Hz Freq.Performance:

L =40 8μm[Bannon 1996]

String (110 Hz)

Stiffnessfo=8.5MHzQvac =8,000

Qair ~50

Lr 40.8μmmr ~ 10-13 kg

Wr=8μm, hr=2μmd=1000Å, VP=5V

ro

kf 1=

Freq. Equation:air , P

Press.=70mTorr


Guitar ro m

fπ2

Freq. Mass

3CC 3λ/4 Bridged μMechanical Filter

VPPerformance:fo=9MHz, BW=20kHz, PBW=0.2%

I L =2 79dB Stop Rej =51dB

0

In OutI.L.=2.79dB, Stop. Rej.=51dB

20dB S.F.=1.95, 40dB S.F.=6.45

-10

0

B]

-30

-20

ssio

n [d

B

Pin=-20dBm Sharper roll-off Design:

L 40-40

Tran

smis

Loss PoleLr=40μm

Wr=6.5μm hr=2μm

L 3 5

-60

-50T Lc=3.5μmLb=1.6μm VP=10.47VP= 5dBm

[S.-S. Li, Nguyen, FCS’05]


8.7 8.9 9.1 9.3Frequency [MHz]

P=-5dBmRQi=RQo=12kΩ

[Li, et al., UFFCS’04]

1.51-GHz, Q=11,555 Nanocrystalline Diamond Disk μMechanical Resonatorm μ

• Impedance-mismatched stem for reduced anchor dissipation

•O t d i th 2nd di l t d•Operated in the 2nd radial-contour mode•Q ~11,555 (vacuum); Q ~10,100 (air)• Below: 20 μm diameter disk Design/Performance:

R 10 t 2 2 d 800Å V 7V

-84

Below: 20 μm diameter disk

Polysilicon Stem(Impedance Mismatched ]

R=10μm, t=2.2μm, d=800Å, VP=7Vfo=1.51 GHz (2nd mode), Q=11,555

§

-90-88-86

P l ili

(Impedance Mismatchedto Diamond Disk)

ude

[dB

]

fo = 1.51 GHzQ = 11,555 (vac)Q = 10,100 (air)

§

96-94-9290Polysilicon

Electrode RA

mpl

itu Q = 10,100 (air)

-100-98-96

1507 4 1507 6 1507 8 1508 1508 2G dCVD DiamondM h i l Di k

Mix

ed A


1507.4 1507.6 1507.8 1508 1508.2GroundPlane

μMechanical DiskResonator Frequency [MHz]

[Wang, Butler, Nguyen MEMS’04]

163-MHz Differential Disk-Array Filter

VFilter Coupler

Com. Array Couplers

vi+ vo+VP

λ/2

Port1 Port3

λ/2

λ/4

λ λ

λ/4

vi- vo-VP

λ/2Port2 Port4

λ/2Diff. Array Couplers


Couplers

[Li, Nguyen Trans’07]

Linear MEMS in Wireless CommsHigh Q and good linearity of micromechanical resonators

Filters for front-end frequency selection

n [d

B]

ansm

issi

on

Frequency [MHz]

Tra

Micromechanical Bandpass Filter

A/DDiplexer

Mixer I LPF I

AGC

Antenna

Wireless Phone

90o0o

RF PLLRF RXRF LO

Xstal Osc

Q

AGC

LNA


A/DFrom TXBPF

Mixer Q LPF

Q

AGC

LNA

Miniaturization of RF Front Ends

Diplexer

925-960MHz

RF Power Amplifier

RF SAW Filter

1805-1880MHz RF SAW Filter

897.5±17.5MHz RF SAW Filter

26-MHz Xstal Oscillator

RF SAW FilterDual-Band Zero-IF

Transistor ChipOscillator

3420-3840MHz VCO

Problem: high-Q passives pose a bottleneck against miniaturization

A/DDiplexer

Mixer I LPF I

AGC

Antenna

Wireless Phone

90o0o

RF PLLRF RXRF LO

Xstal Osc

Q

AGC

LNA


A/DFrom TXBPF

Mixer Q LPF

Q

AGC

LNA

I

Multi-Band Wireless Handsets

LPF

Duplexer

LNA RF BPFCDMACDMA

0o

I

A/D IAGCRF BPF GSM 900GSM 900

From TX90o

0o

Antenna

A/DI

LPF

QAGC

RF BPF PCS 1900PCS 1900

LNA Q

90o0o

RXRF LO

LNA

LNARF BPF DCS 1800DCS 1800 ÷ (N+1)/N Xstal

OscRXRF ChannelSelect PLL

Q

Duplexer RF BPF

LNA

LNA

CDMACDMA--20002000 Tank

Duplexer

LNAFrom TX

RF BPF

CDMACDMA 20002000

• The number of off-chip high-Qpassives increases dramatically


LNAWCDMAWCDMA From TX

passives increases dramatically•Need: on-chip high-Q passives

All High-Q Passives on a Single Chip

0.25 mm

Vibrating Resonator62-MHz, Q~161,000

Vibrating Resonator1.5-GHz, Q~12,000

GSM 900 RF Filter

CDMA RF Filters(869-894 MHz) Optional RF

Oscillator Ultra-High Q

PCS 1900 RF Filter(1930-1990 MHz)

(935-960 MHz)

Low Freq.

Ultra-High QTanks

CDMA 2000

DCS 1800 RF Filter(1805-1880 MHz)

Low Freq. Reference Oscillator Ultra-High

Q Tank

WCDMA

CDMA-2000RF Filters

(1850-1990 MHz)

Q Tank


WCDMARF Filters

(2110-2170 MHz)

Chip-Scale Atomic Clocks (CSAC)Chip Scale Atomic Clocks (CSAC)


NIST F1 Fountain Atomic Clock

Vol: ~3.7 mVol: ~3.7 m33

Power: ~500 WPower: ~500 WAcc: Acc: 11××1010––1515

Stab: 3.3x10Stab: 3.3x10--1515/hr/hr

After 1 sec Error: 10-15 sec

Loses 1 sec every y30 million years!


Physics Package

Benefits of Accurate Portable TimingNetworked Sensors

Better Timing

Secure CommunicationsLarger networks withMore efficient

spectrum utilizationLarger networks with

longer autonomy

Faster frequency hop rates

Longer autonomy periods GPS

Faster acquire of pseudorandom signals

Fewer satellites needed

Superior resilience Higher jamming

margin


pagainst jamming or

interception Faster GPS acquire

NIST F1 Fountain Atomic Clock

Vol: ~3.7 mVol: ~3.7 m33

Power: ~500 WPower: ~500 WAcc: Acc: 11××1010––1515

Stab: 3.3x10Stab: 3.3x10--1515/hr/hr

After 1 sec Error: 10-15 sec

Loses 1 sec every y30 million years!


Physics Package

Tiny Physics Package Performance• Experimental Conditions:

Cs D2 ExcitationExternal (large) Magnetic Shielding

Dime

NIST’s Chip-Scale

External (large) Magnetic ShieldingExternal Electronics & LO Cell Temperature: ~80 ºCCell Heater Power: 69 mWC p Sca e

Atomic Physics Package

Cell Heater Power: 69 mWLaser Current/Voltage: 2mA / 2VRF Laser Mod Power: 70μW

Open Loop Resonance: Drift to Be Removed

10-9σ y

Stability Measurement:Drift IssueCs (D2)

5.67

[V]

7.1 kHz

Removed in Phase 3

Sufficient to meet

10-10

Dev

iatio

n,

Q =1.3x106

5.66

PD S

igna

l

Contrast: 0.91% 2.4e-10 Allandeviation @ 1 s

to meet CSAC

program goals

10-11

Alla

n D

Rb (D1) 1 day1 day1 hour1 hour


40 50 60 70 80 905.65

Frequency Detuning, Δ [kHz] from 9,192,631,770 Hz

100 101 102 103 104 10510-12

Integration Time, τ [s]

1 day1 day1 hour1 hour

Documents

EE C245 – ME C218 Introduction to MEMS Design Fall 2008 · PDF fileEE C245 – ME C218 Introduction to MEMS Design ... Benefits of Scaling. ... Benefits of Size Reduction: MEMS