From MEMS to NEMS: Smaller Is Still Betterctnguyen/...C. T.-C. Nguyen, “From MEMS to NEMS: Smaller Is Still Better,” MARC’06 Meeting, 1/25-26/05 DARPA Other Common Attributes

C. T.-C. Nguyen, “From MEMS to NEMS: Smaller Is Still Better,” MARC’06 Meeting, 1/25-26/05

DARPADARPA

From MEMS to NEMS: Smaller Is Still Better

Clark T.-C. Nguyen

Dept. of Electrical Engineering & Computer ScienceUniversity of Michigan

Ann Arbor, Michigan 48105-2122

(Last Month: Program Manager, DARPA/MTO)

MARC’06 MeetingJan. 25-26, 2006


DARPADARPA Outline

• Introduction:MEMS technologyintegration with transistors: an early driver for MEMS

• Benefits of Scalingsize reductionspeed, energy conservation, complexity, economy

• DARPA/MTO Program ExamplesNano Mechanical Array Signal Processors (NMASP)Chip-Scale Atomic Clock (CSAC)Micro Gas Analyzers (MGA)

• Conclusions (What’s Next?)


DARPADARPA

Angle set by mechanical meansto control the path of light

MEMS:MEMS: MMicro EElectro MMechanical SSystems

• A device constructed using micromachining (MEMS) tech.• A micro-scale or smaller device/system that operates mainly

via a mechanical or electromechanical means• At least some of the signals flowing through a MEMS device

are best described in terms of mechanical variables, e.g., displacement, velocity, acceleration, temperature, flow

MEMS

Input:voltage, current

acceleration, velocitylight, heat …

Output:voltage, current

acceleration, velocitylight, heat, …

Control:voltage, current

acceleration velocity

light, heat, …

[Wu, UCLA]Transducer to

Convert Controlto a Mechanical Variable (e.g., displacement,

velocity, stress, heat, …)

Transducer to Convert Controlto a Mechanical Variable (e.g., displacement,

velocity, stress, heat, …)


DARPADARPA Other Common Attributes of MEMS

• Feature sizes measured in microns or less

• Merges computation with sensing and actuation to change the way we perceive and control the physical world

• Planar lithographic technology often used for fabricationcan use fab equipment identical to those needed for IC’showever, some fabrication steps transcend those of conventional IC processing

MEMSTechnology

Gimballed, SpinningMacro-Gyroscope

MicromechanicalVibrating Ring Gyroscope

Signal Conditioning Circuits

80 mm

1 mm

(for 80X sizeReduction)

[Najafi, Michigan]


DARPADARPA

Silicon Substrate

Glass Substrate

Bulk Micromachining and Bonding

• Use the wafer itself as the structural material

• Adv: very large aspect ratios, thick structures

• Example: deep etching and wafer bonding

Silicon SubstrateSilicon Substrate

Glass Substrate

Silicon Substrate

Metal InterconnectAnchor

MovableStructure Electrode

MicromechanicalVibrating Ring Gyroscope

1 mm

Microrotor(for a microengine)

[Najafi, Michigan] [Pisano, UC Berkeley][Pisano, UC Berkeley]


DARPADARPA

• Fabrication steps compatible with planar IC processing

Surface Micromachining


DARPADARPA

• Completely monolithic, low phase noise, high-Q oscillator (effectively, an integrated crystal oscillator)

• To allow the use of >600oC processing temperatures, tungsten (instead of aluminum) is used for metallization

OscilloscopeOutput

Waveform

Single-Chip Ckt/MEMS Integration

[Nguyen, Howe 1993][Nguyen, Howe 1993]


DARPADARPA Technology Trend and Roadmap for MEMSin

crea

sing

abi

lity

to c

ompu

te

increasing ability to sense and act

Num

ber o

f Tra

nsis

tors

Number of Mechanical Components

100

101

102

103

104

105

106

107

108

109

100 101 102 103 104 105 106 107 108 109

AdaptiveOptics

Integrated FluidicSystems

DistributedStructural

ControlTerabit/cm2

Data Storage

Optical Switches& Aligners

InertialNavigationOn a Chip

Displays

Weapons,Safing, Arming,

and Fusing

Majority ofEarly MEMS

Devices(mostly sensors)

ADXL-50

Digital MicromirrorDevice (DMD)

ADXL-278

Future MEMSIntegration Levels

Enabled Applications

OMM 32x32

ADXL-78

CPU’s

Pentium 4

ADXRS

i-STAT 1Caliper

Phased-ArrayAntenna


DARPADARPA Benefits of Size Reduction: IC’s

• Numerous benefits attained by scaling of transistors:

FasterSpeed

Higher Current DriveLower Capacitance

Higher Integration DensityLower Supply Voltage

LowerPower

Higher Circuit Complexity & Economy of Scale

• But … some drawbacks:poorer reliability (e.g., hot e- effects)lower dynamic range (analog ckts suffer)


DARPADARPA Example: Micromechanical Accelerometer

• The MEMS Advantage:>30X size reduction for accelerometer mechanical elementallows integration with IC’s

xo

x

a

Acceleration

Inertial Force

Spring

Proof Mass

Basic Operation Principle

400

μm

Analog Devices ADXL 78

Displacement

maFx i =∝

Tiny mass means small output need integrated transistor

circuits to compensate




DARPADARPA

DisplaysPhased-ArrayAntenna

Technology Trend and Roadmap for MEMSin

crea

sing

abi

lity

to c

ompu

te

increasing ability to sense and act

Num

ber o

f Tra

nsis

tors

Number of Mechanical Components

100

101

102

103

104

105

106

107

108

109

100 101 102 103 104 105 106 107 108 109

AdaptiveOptics

Integrated FluidicSystems

DistributedStructural

ControlTerabit/cm2

Data Storage

Optical Switches& Aligners

InertialNavigationOn a Chip

Weapons,Safing, Arming,

and Fusing

Majority ofEarly MEMS

Devices(mostly sensors)

ADXL-50

Digital MicromirrorDevice (DMD)

ADXL-278

Future MEMSIntegration Levels

Enabled Applications

OMM 32x32

ADXL-78

CPU’s

Pentium 4

i-STAT 1

ADXRSCaliper Microfluidic Chip

Adv.: small size, small sample, fast analysis speed

Adv.: small size, small sample, fast analysis speed

Caliper

Analog Devices ADXRSIntegrated Gyroscope

Adv.: small sizeAdv.: small size

OMM 8x8 OpticalCross-Connect Switch

Adv.: faster switching, low loss, larger networks

Adv.: faster switching, low loss, larger networks

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

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

TI Digital Micromirror Device


DARPADARPA Benefits of Size Reduction: MEMS

• Benefits of size reduction clear for IC’s in elect. domainsize reduction speed, low power, complexity, economy

• MEMS: enables a similar concept, but …

MEMS extends the benefits of size reductionbeyond the electrical domain

Performance enhancements for applicationdomains beyond those satisfied by electronics

in the same general categories Speed

Power ConsumptionComplexity

Economy

Frequency , Thermal Time Const. Actuation Energy , Heating Power Integration Density , Functionality Batch Fab. Pot. (esp. for packaging)


DARPADARPA

Nano Mechanical Array Signal Processors (NMASP)


DARPADARPA Basic Concept: Scaling Guitar StringsGuitar String

Guitar

Vibrating “A”String (110 Hz)Vibrating “A”

String (110 Hz)

High Q

110 Hz Freq.

Vib.

Am

plitu

de

Low Q

r

ro m

kfπ21

=

Freq. Equation:

Freq.

Stiffness

Mass

fo=8.5MHzQvac =8,000

Qair ~50

μMechanical Resonator

Performance:Lr=40.8μm

mr ~ 10-13 kgWr=8μm, hr=2μmd=1000Å, VP=5VPress.=70mTorr

[Bannon 1996]


DARPADARPA

-60

-50

-40

-30

-20

-10

0

8.7 8.9 9.1 9.3Frequency [MHz]

Tran

smis

sion

[dB

]

Pin=-20dBm

In Out

VP

Sharper roll-off

Sharper roll-off

Loss PoleLoss Pole

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

I.L.=2.79dB, Stop. Rej.=51dB20dB S.F.=1.95, 40dB S.F.=6.45

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

I.L.=2.79dB, Stop. Rej.=51dB20dB S.F.=1.95, 40dB S.F.=6.45

Design:Lr=40μm

Wr=6.5μm hr=2μm

Lc=3.5μmLb=1.6μm VP=10.47VP=-5dBm

RQi=RQo=12kΩ

[S.-S. Li, Nguyen, FCS’05]

3CC 3λ/4 Bridged μMechanical Filter

[Li, et al., UFFCS’04]


DARPADARPA

• Constructed in SiC material w/ 30 nm Al metallization for magnetomotive pickup

Lr

Wr

h

Frequency [GHz]

Mag

neto

mot

ive

Res

p. [n

V]

Design/Performance:Lr =1.1 μm, Wr =120 nm, h= 75 nm

fo=1.029 GHz, Q =500 @ 4K, vacuum

Design/Performance:Lr =1.1 μm, Wr =120 nm, h= 75 nm

fo=1.029 GHz, Q =500 @ 4K, vacuum

[Roukes, Zorman 2002]

Nanomechanical Vibrating Resonator


DARPADARPA Scaling-Induced Performance Limitations

Mass Loading Noise

• Differences in rates of adsorption and desorption of contaminant molecules

mass fluctuationsfrequency fluctuations

Temperature Fluctuation Noise

• Absorption/emission of photons

temperature fluctuationsfrequency fluctuations

ContaminantMolecules

NanoresonatorMass ~10-17 kg

mk

2π1

of =

Photons

NanoresonatorVolume ~10-21 m3

• Problem: if dimensions too small phase noise significant!• Solution: operate under optimum pressure and temperature

[J. R. Vig, 1999]


DARPADARPA

-100-98-96-94-92-90-88-86-84

1507.4 1507.6 1507.8 1508 1508.2

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

• Impedance-mismatched stem for reduced anchor dissipation

• Operated in the 2nd radial-contour mode• Q ~11,555 (vacuum); Q ~10,100 (air)• Below: 20 μm diameter disk

PolysiliconElectrode R

Polysilicon Stem(Impedance Mismatched

to Diamond Disk)

GroundPlane

CVD DiamondμMechanical Disk

Resonator Frequency [MHz]

Mix

ed A

mpl

itude

[dB

]

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

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

[Wang, Butler, Nguyen MEMS’04]

Q = 10,100 (air)


DARPADARPA

Wireless Phone

Miniaturization of RF Front Ends

26-MHz XstalOscillator

26-MHz XstalOscillator

DiplexerDiplexer

925-960MHz RF SAW Filter925-960MHz

RF SAW Filter

1805-1880MHz RF SAW Filter

1805-1880MHz RF SAW Filter

897.5±17.5MHz RF SAW Filter

897.5±17.5MHz RF SAW Filter

RF Power Amplifier

RF Power Amplifier

Dual-Band Zero-IF Transistor Chip

Dual-Band Zero-IF Transistor Chip

3420-3840MHz VCO

3420-3840MHz VCO

90o0o

A/D

A/D

RF PLL

Diplexer

From TX

RF BPF

Mixer I

Mixer Q

LPF

LPF

RXRF LO

XstalOsc

I

Q

AGC

AGC

LNA

Antenna

Problem: high-Q passives pose a bottleneck against miniaturizationProblem: high-Q passives pose a bottleneck against miniaturization


DARPADARPA

Wireless Phone

Raised Inductor Q ~30-70

Raised Inductor Q ~30-70

Planar Spiral Inductor

Planar Spiral Inductor

Q <10 too small

Q <10 too small

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

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

Vibrating Resonator72-MHz, Q~146,000

Vibrating Resonator72-MHz, Q~146,000

Single-ChipRealization

Miniaturization of RF Front Ends


DARPADARPA

Chip-Scale Atomic Clocks (CSAC)


DARPADARPA NIST F1 Fountain Atomic Clock

VolVol: ~3.7 m: ~3.7 m33

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

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

Physics PackagePhysics Package

After 1 sec Error: 10-15 secAfter 1 sec

Error: 10-15 sec

Loses 1 sec every 30 million years!

Loses 1 sec every 30 million years!


DARPADARPA Benefits of Accurate Portable Timing

Secure Communications

Networked Sensors

Faster frequency hop ratesFaster frequency hop rates

Faster acquire of pseudorandom signals

Faster acquire of pseudorandom signals

Superior resilience against jamming or

interception

Superior resilience against jamming or

interception

More efficient spectrum utilization

More efficient spectrum utilization

Longer autonomy periodsLonger autonomy periods GPS

Faster GPS acquireFaster GPS acquire

Higher jamming margin

Higher jamming margin

Fewer satellites needed

Fewer satellites needed

Larger networks with longer autonomy

Larger networks with longer autonomy

Better TimingBetter Timing


DARPADARPA Accurate Portable Timekeepers

• Stability quite good at carrier offset freqs. around 1 kHz

• L{fm=1kHz} = -140dBc/Hz

High-Q Oscillators• Tank Q ~ tens of thousands• Example: crystal oscillator

• Quartz: vibrating mechanical resonance high Q, stable

10MHz

Shear Mode

Excellent stability at offset

frequencies ~1kHz

Excellent stability at offset

frequencies ~1kHz

Accuracy (@ tiny offset freqs.) good,

but not good enough for some applications

Accuracy (@ tiny offset freqs.) good,

but not good enough for some applications


DARPADARPA Atomic Clock Fundamentals

133Cs

m = 0f = 4

m = 0f = 3

m = 1

• Frequency determined by an atomic transition energy

Energy Band Diagram

Excite e- to the next orbital

Excite e- to the next orbital

Opposite e- spins

Opposite e- spins

ΔE = 0.000038 eV

ΔE = 1.46 eV

ν = ΔE/h= 352 THz852.11 nm

ν = ΔE/ħ= 9 192 631 770 Hz


DARPADARPA Miniature Atomic Clock Design

ν = ΔE/ħ= 9 192 631 770 Hz

HyperfineSplitting Freq.

HyperfineSplitting Freq.

Sidebands

ModulatedLaser

PhotoDetector

133Cs vapor at 10–7 torr

Mod f

μwave osc

VCXO4.6 GHz

9.2GHz

4.6GHz

Atoms become transparent to light at 852 nm

Atoms become transparent to light at 852 nm

Carrier(852 nm)

λ

Close feedback loop to lock

Close feedback loop to lock

vo


DARPADARPA

State-of-Practice

State-of-Research

Datum R2000Vol: 9,050 cm3

Power: 60 WAcc: 5×10–11

Temex RMOVol: 230 cm3

Power: 10 WAcc: 1×10–11

NISTNIST-- F1F1

CSACCSAC

VolVol: 1 cm: 1 cm33

Power: 30 Power: 30 mWmWAcc: 1x10Acc: 1x10--1111

Stab: Stab: 11××1010––1111/hr/hr

Miniaturizing Atomic Clocks

VolVol: ~3.7 m: ~3.7 m33

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

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

μs/dayμs/day

ps/dayps/day


DARPADARPA Chip-Scale Atomic Clock

• Key Challenges:thermal isolation for low powercell design for maximum Qlow power μwave oscillator

Atomic Clock Concept Cs or Cs or RbRbGlassGlassDetectorDetector

VCSELVCSEL

SubstrateSubstrate

GHzGHzResonatorResonatorin Vacuumin Vacuum

MEMS andMEMS andPhotonic Photonic

TechnologiesTechnologies


Power: 30 Power: 30 mWmWStab: Stab: 11××1010––1111

Chip-ScaleAtomic Clock

Laser 133Cs vapor at 10–7 torr

Mod f

μwave oscVCXO

4.6 GHzvo PhotoDetector


DARPADARPA

Pros and Cons of Miniaturization


DARPADARPA

Rth= 18 K/WCth= 40 J/K

Rth= 18 K/WCth= 40 J/K Rth= 61,000 K/W

Cth= 4.8x10-5 J/KRth= 61,000 K/WCth= 4.8x10-5 J/K

P RthCth

T = P x Rth

Cth ~ volume

Rth ~ support lengthX-section area

Macro-Scale Micro-Scale

P (@ 80oC) = 1 mWP (@ 80oC) = 1 mW

Warm Up, τ = 3 sWarm Up, τ = 3 s

P (@ 80oC) = 3 WP (@ 80oC) = 3 W

Warm Up, τ = 12 min.Warm Up, τ = 12 min.

3,000x lower power3,000x lower power

240x faster warm up240x faster warm up

300x300x300 μm3

Atomic Cell @ 80oC

Long, Thin Nitride

Tethers w/ Metal Leads

T Sensor(underneath)

Heater

LaserInsulation

Macro-Oven(containing heater

and T sensor)2 cm3

Atomic Cell @ 80oC

Thermally Isolating Feet

Laser25oC

2 cm

Micro-Scale Oven-Control Advantages


DARPADARPA Challenge: Miniature Atomic CellLarge Vapor Cell Tiny Vapor Cell

1,000XVolumeScaling

Wall collision dephasesatoms lose coherent state

Wall collision dephasesatoms lose coherent state

Inte

nsity

Mod f9.2 GHz

SurfaceVolume

More wall collisions stability gets worse

More wall collisions stability gets worse

lower Qlower Q

lowest Qlowest QAtomic

Resonance


DARPADARPA Challenge: Miniature Atomic CellLarge Vapor Cell Tiny Vapor Cell

1,000XVolumeScaling

Inte

nsity

Mod f9.2 GHz

Atomic Resonance

Soln: Add a buffer gas

Soln: Add a buffer gas

Lower the mean free path of the atomic vapor

Lower the mean free path of the atomic vapor

Return to higher Q

Return to higher Q

Buffer Gas


DARPADARPA

1.5 mm

4.2 mm

1.5 mm

Laser

Optics

Cell

Photodiode

1 mm

Total Volume: 9.5 mm3 Stability: 2.4 x 10-10 @ 1sCell Interior Vol: 0.6 mm3 Power Cons: 75 mW

Total Volume: 9.5 mm3 Stability: 2.4 x 10-10 @ 1sCell Interior Vol: 0.6 mm3 Power Cons: 75 mW

1st Chip-Scale Atomic Physics Package

GlassND

SiQuartz

ND

Lens

Alumina

VCSEL


DARPADARPA Tiny Physics Package Performance

NIST’sChip-Scale

Atomic Physics Package

NIST’sChip-Scale

Atomic Physics Package

40 50 60 70 80 905.65

5.66

5.67

PD S

igna

l [V]

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

7.1 kHz

Contrast: 0.91% 2.4e-10 Allandeviation @ 1 s2.4e-10 Allan

deviation @ 1 s

• Experimental Conditions:Cs D2 ExcitationExternal (large) Magnetic ShieldingExternal Electronics & LO Cell Temperature: ~80 ºCCell Heater Power: 69 mWLaser Current/Voltage: 2mA / 2VRF Laser Mod Power: 70μW

DimeDime

Open Loop Resonance:Drift to Be Removed in Phase 3

Drift to Be Removed in Phase 3

Sufficient to meet CSAC

program goals

Sufficient to meet CSAC

program goals

100 101 102 103 104 10510-12

10-11

10-10

10-9

Alla

n D

evia

tion,

σy

Integration Time, τ [s]

Stability Measurement:

Drift IssueDrift Issue

Rb (D1)Rb (D1) 1 day1 day1 hour1 hour

Cs (D2)Cs (D2)

Q =1.3x106Q =1.3x106

CSAC Goal


DARPADARPA Physics Package Power Diss. < 10 mW

Heater/Sensor SuspensionCesium cell

Frame Spacer

VCSEL Suspension

VCSEL / Photodiode 20 pin LCC

7 mm

0

2

4

6

8

10

12

0 20 40 60 80 100 120 140Temperature [oC]

Pow

er [m

W] Measured

Model

Only ~5 mWheating power

needed to achieve 80oC

cell temperature

Only ~5 mWheating power

needed to achieve 80oC

cell temperature

• Achieved via MEMS-based thermal isolation

Symmetricom / Draper Physics

Package Assembly

Symmetricom / Draper Physics

Package Assembly


DARPADARPA A 9.95 cc, 153 mW Atomic Clock w/ Chip-Scale Physics Package

3.94 cm

3.53

cm


Symmetricom’smeasured Allan deviation easily satisfies CSAC Phase 2 Goal

Symmetricom’smeasured Allan deviation easily satisfies CSAC Phase 2 Goal

0.47 cm

Packaged CSAC

153 mWTotal:

10 mWC-field

51 mWHeater Power (air)

2 mWVCSEL drive

75 mWRF

6 mWSignal Processing

8 mWMicroprocessor

1 mWPower Regulation


1.43 cmPower Budget < 200 mW0.64 cm

9.95 cm3 Total Package Volume9.95 cm3 Total

Package Volume

MEMS-based thermal isolation allows low physics package power consumption

MEMS-based thermal isolation allows low physics package power consumption

5x10-10

@ 1 sec5x10-10

@ 1 sec

CSAC Phase 2 Goal


DARPADARPA Atomic Clock Technology Progression

State-of-Practice

State-of-Research

HP 5071AVol: 29,700 cm3

Power: 50 WAcc: 5×10–13

Datum R2000Vol: 9,050 cm3

Power: 60 WAcc: 5×10–11

Temex RMOVol: 230 cm3

Power: 10 WAcc: 1×10–11

NISTPP Vol: 9.5 mm3

Power: 75 mW+elect.Stab: 10–11/hr

Symmetricom CSACVol: 9.95 cm3

Power: 153 mWStab: 5×10–11/100s

NISTNIST-- F1F1

VolVol: ~3.7 m: ~3.7 m33

Power: ~500 WPower: ~500 WAcc: Acc: 3.83.8××1010––1515

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


Power: 30 Power: 30 mWmWAcc: 1x10Acc: 1x10--1111

Stab: Stab: 11××1010––1111/hr/hr

Stab = Allan deviation/integration time

Stab = Allan deviation/integration time



DARPADARPA

Micro Gas Analyzers (MGA)


DARPADARPA

Gas SensitivePolymer

CapacitorPlates

Conventional Sensor Separation Analyzer

Micro Gas Analyzers• Objective: enable remote detection of chemical agents via tiny,

ultra-low power, fast, chip-scale gas analyzers that greatly reduce the incidence of false positives

• Approach: use micromachining technologies to implement separation-based analyzers (e.g., gas chromatographs, mass spectrometers) at the micro-scale to enhance gas selectivity

ΔC ~gas conc.

Species A Species B

• Problem: polymer has finite sensitivity to both A & B

Species A

B

A

B

• Result: species A & B now separated can identify and analyze individually

• Problem: too big, too slow, power hungry


DARPADARPA Advantages of Miniaturization

Portable Gas Chromatograph Chip-Scale Gas Chromatograph

Reduction FactorsReduction FactorsReduction Factors

13″

19″ Depth = 10″Preconcentrator Detector Array

5 m

m

SeparationColumn

1-2 cmMicropump

Size 40,500 cm3

Sensitivity 1 ppb

Analysis Time 15 min.

Energy Per Analysis 10,000 J

Size 2 cm3

Sensitivity 1 ppt

Analysis Time 4 sec

Energy Per Analysis 1 J

225X225X225X

10,000X10,000X10,000X

20,000X20,000X20,000X

1,000X1,000X1,000X


DARPADARPA Basic Approach: Separation Analyzer

Input GasMixture Pre-Concentrator Separator Detector

ElectronicProcessor

ThreeAnalytes

CompactedSlice of

Analytes

SeparatedAnalytes

Pump

Tiny Dimensionsfast time constants10,000X gain factor via multi-stagingenhanced sensitivitylower power


Min

iatu

rizat

ion


DARPADARPA Multi-Stage Pre-Concentration

ToSeparator

[Honeywell]

AbsorbentFilmHeater

Incoming GasMixture

Release Analytein Phase

Release Analytein Phase

Thin Concentrated PlugThin Concentrated Plug

Heat ~2mW to Release

Analyte

Heat ~2mW to Release

Analyte

10 ppb10 ppb

1,000 ppb1,000 ppb

2,000 ppb2,000 ppb

3,000 ppb3,000 ppb 5,000 ppb5,000 ppb


DARPADARPA Fast PHASED Pre-Concentration

• Below: 20-stage PHASED preconc./sep. analysis of a 720 ppmHexane-in-Air sample at 60 cm/s sample velocity

PHASED chip with 20-stage

preconcentratorand separator

PHASED chip with 20-stage

preconcentratorand separator

Only 300ms needed for sample

absorption @ 20oC!

Only 300ms needed for sample

absorption @ 20oC!300 ms300 ms

Sample Expulsion @ 120oC

Sample Expulsion @ 120oC




ElectronicProcessor

ThreeAnalytes

CompactedSlice of

Analytes

SeparatedAnalytes

Pump



Tiny Dimensionsfaster separationlower power


Min

iatu

rizat

ion


DARPADARPA Scaling Leads to Faster Separation

• Example: gas chromatograph separation column

unique analyte interactions with the column wallsdifferent analyte velocitiesresult: separation after a finite distance

WideChannel

ThinChannel

240 μm

150 μm

StationaryPhase

Carrier Gas (Mobile Phase)Miniaturize

x

Conc. Conc.

x

PeakBroadens

PeakStays Thin

LessSeparationNeeded toResolve


DARPADARPA Scaling Leads to Faster Separation

• Example: gas chromatograph separation column

unique analyte interactions with the column wallsdifferent analyte velocitiesresult: separation after a finite distance

WideChannel

ThinChannel

240 μm

150 μm

StationaryPhase

Carrier Gas (Mobile Phase)Miniaturize

• Result of Scaling: shorter column length; faster analysis time

Surface-to-Volume Ratio

PeakSpreading

SeparationDistance

ColumnWidth


DARPADARPA Gas Chromatography in Less Than 4s!

Solv

ent

Tolu

ene

DM

MP

DEM

P

DIM

P n-do

deca

ne

1-de

cano

l

3-m

ethy

lhex

ane

0 1.2 2.4 3.6 4.8

16000

32000

46000

64000

Elution time [s]

80000

Rel

ativ

e In

tens

ity

Peak capacity >40, in 4 sec

Peak capacity >40, in 4 sec

Sandia’s micro-GC ColumnSandia’s micro-GC Column

Design/Measurement Data:0.75m x 100μ column

0.1μ DB-5 stationary phaseHeart-cut 275 msec peak injection

Temperature: ~30 deg C/secH2 carrier: 35-39 psi at 1 psi/sec

Design/Measurement Data:0.75m x 100μ column

0.1μ DB-5 stationary phaseHeart-cut 275 msec peak injection

Temperature: ~30 deg C/secH2 carrier: 35-39 psi at 1 psi/sec

1,6-

dich

loro

hexa

ne Green = AnalyteBlue = Inteferent

Green = AnalyteBlue = Inteferent




ElectronicProcessor

ThreeAnalytes

CompactedSlice of

Analytes

SeparatedAnalytes

Pump





Tiny Dimensionshigher sensitivityfaster refresh ratelower powerarrays for specificity

Tiny Dimensionshigher sensitivityfaster refresh ratelower powerarrays for specificity

Min

iatu

rizat

ion


DARPADARPA Zeptogram Mass Sensors

0 50 100 150 200 250 300 350

-1000

-800

-600

-400

-200

0

Freq

uenc

y S

hift

(Hz)

Time (sec)

~100 zg

Nozzle

ShutterNanomechanicalResonator

0 1000 2000 3000 4000-3000

-2500

-2000

-1500

-1000

-500

0

133 MHz190 MHz

Freq

uenc

y S

hift

(Hz)

Mass (zeptograms)

0 2000 40000.1

1

10

100

δ m (

zg)

Time (s)

~7 zg

>1Hz/zg100 zg Au atom

clumps resolved!100 zg Au atom

clumps resolved!

Nanomechanical ResonatorNanomechanical Resonator

Measurement noise level indicates ~7 zg of resolutionMeasurement noise level

indicates ~7 zg of resolution

Au


DARPADARPA

• Example: ion trap mass spectrometer (ITMS)separate analytes by molecular weight

• Advantages of Miniaturization:can support smaller mean free path relaxed vacuum req.result: substantially lower power requirement

ITMS: Scaling Leads to Lower Power

vRF

Detector

DetectorVRF

time

time

DetectorOutput

100 ms TrappedIons

Stability Thresholds(dependent on mass)


DARPADARPA Operation at 1.7 Torr!

80 90 100 110 120

0.04

0.08

0.12

0.16

Det

ecto

r Cur

rent

[pA

]

m/z

Mass spectrum of DMMP by a single 1-mm ion trap @ 1.7 TorrMass spectrum of DMMP by a

single 1-mm ion trap @ 1.7 Torr

Resistive Glass Drift Tube DetectorResistive Glass

Drift Tube Detector

Test Jig (vacuum chamber insert)

Test Jig (vacuum chamber insert)

ChanneltronDetector

ChanneltronDetector

Highest pressure ever demonstrated!Highest pressure

ever demonstrated!

1mm Cylindrical Ion Trap1mm Cylindrical Ion Trap


DARPADARPA 40μm-Ion Traps Functional!

• Should allow much higher pressure operation (~76 Torr)

Xe ion peakXe ion peak

Array of 40μm Si Ion TrapsArray of 40μm Si Ion Traps

Silicon

Heavily-Doped Polysilicon Oxide Aluminum

Xenon signal obtained at low He pressure (10-4 Torr)Xenon signal obtained at

low He pressure (10-4 Torr)


DARPADARPA Gas Analyzer Technology Progression

LLNLVol: 40,500 cm3

Power: 11.5 WEnergy/Analysis: 10 kJAnalysis Time: 15 min.

MGA ObjectiveMGA ObjectiveVolVol: 2 cm: 2 cm33

Power: <200 Power: <200 mWmWEnergy/Analysis: 1 JEnergy/Analysis: 1 J

Analysis Time: 4 sAnalysis Time: 4 s

Agilent 6852AVol: 60,000 cm3

Power: 20 WEnergy/Analysis: 18 kJAnalysis Time: 15 min.

Sandia μChem LabVol: 1,050 cm3

Power: 4.5 WEnergy/Analysis: 540 JAnalysis Time: 2 min.

Gas Chromatograph/Mass Spectrometer (GC/MS) is

a “gold standard” in chemical gas detection with excellent immunity

to false alarms

Gas Chromatograph/Mass Spectrometer (GC/MS) is

a “gold standard” in chemical gas detection with excellent immunity

to false alarms

Problems: too big, too slow, power hungry

Problems: too big, too slow, power hungry

Solution: use MEMS technology to miniaturize the GC/MS, which in turn makes it faster and more

energy efficient

Solution: use MEMS technology to miniaturize the GC/MS, which in turn makes it faster and more

energy efficient

small enough for projectile delivery1 ppt det. limitvery fastbattery operable

small enough for projectile delivery1 ppt det. limitvery fastbattery operable


DARPADARPA Example: Micromechanical Accelerometer

• The MEMS Advantage:>30X size reduction for accelerometer mechanical elementallows integration with IC’s

xo

x

a

Acceleration

Inertial Force

Spring

Proof Mass

Basic Operation Principle

400

μm

Analog Devices ADXL 78

Displacement

maFx i =∝






DARPADARPA Conclusions

• MEMS are micro-scale or smaller devices/systems that operate mainly via a mechanical or electromechanical means

• MEMS NEMS offer the same scaling advantages that IC technology offers (e.g., speed, low power, complexity, cost), but they do so for domains beyond electronics:

• Micro … nano … it’s all good• Just as important: MEMS or NEMS have brought together

people from diverse disciplines this is the key to growth!• What’s next? Nano-nuclear fusion? Chip-scale atomic

sensors? … limitless possibilities …

resonant frequency (faster speed)actuation force (lower power)

# mechanical elements (higher complexity)integration level (lower cost)

Size

From MEMS to NEMS: Smaller Is Still Betterctnguyen/...C. T.-C. Nguyen, “From MEMS to NEMS: Smaller Is Still Better,” MARC’06 Meeting, 1/25-26/05 DARPA Other Common Attributes

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