3. Jessen - AOARD Physics

8/7/2019 3. Jessen - AOARD Physics

http://slidepdf.com/reader/full/3-jessen-aoard-physics 1/26

AOARD Physics & Electronics16 March 2011

Gregg JessenProgram Manager

AFOSR/AOARD

Air Force Office of Scientific Research

Distribution A: Approved for public release; distribution is unlimited. 88ABW-2011-0761

AFOSR



2

2011 AFOSR SPRING REVIEWAOARD Physics & Electronics

NAME: Gregg Jessen

BRIEF DESCRIPTION OF PORTFOLIO:Physics and electronics in Asia. Covers theoretical and experimentalaspects of new technologies in the areas of electronic devices, opticaldevices, nanotechnology and enabling materials over the entire

electro-magnetic spectrum. Provide support for domestic programsas needed.

Strategy for sub-area selection:1. Interesting new science2. Customer/need driven3. Funds

LIST SUB-AREAS IN PORTFOLIO:Thin-film transistors, tunable metamaterials, wide-bandgap materials,reliability physics, bio-inspired nano-fabrication, topological insulators

Needs

Funds Interest

Scope

Opportunity!



3

Challenges and Opportunities

• CSWAP (Cost, Size, Weight, and Power) is acontinuous challenge

• Limitations are fundamental capacitance limitingspeed, fundamental understanding of

particle/quasi-particle interaction• Design of new materials to perform new functions

and availability of such materials

• Scaling challenges in terms of both devicephysics and techniques to produce ultra-lowdimensions

• Improving performance of low-cost devices

• Fundamental physical understanding of failuremechanisms of electronic devices

TopologicalInsulators

Activelytunable

metamaterials

Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



4

AOARD Physics & ElectronicsProgram Trends

• Low-cost, high performance electronics: (InGa)ZnOTFTs

• Novel fabrication techniques: Bio-nano devices

• Topological insulators

• Reliability physics (MURI and support projects)• Actively tunable metamaterials – plasma, capacitor,

FET, slow light

• Wireless interconnects: Open ring resonators

• E/M simulation: Inverse scattering algorithms

• Materials growth and characterization: Widebandgap

• THz sources

• Graphene FETs, CNT films



5


• For physics and electronics, CSWAP (Cost, Size,Weight, and Power) is a continuous challenge

• Limitations are fundamental capacitance limitingspeed, fundamental understanding ofparticle/quasi-particle interaction

• Design of new materials to perform new functionsand availability of such materials

• Scaling challenges in terms of both devicephysics and techniques to produce ultra-low

dimensions• Cost of production and improving device

performance for economical devices



Activelytunable

metamaterials

Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



6

• Search for new topological insulatormaterials

• Exploring ternary chalcogenidesbased on theoretical predictions

• Address material quality issuesinterfering with advanced transportmeasurements

• Could fabricate TI-ferromagnetdevices

• Spintronics, sensitive microwavedetectors, quantum computing

Challenges/Opportunities:

New class of materials that are internally insulating with a spin polarized conductive surface.Entirely new classes of electronic devices are possible.

New Science: Finding materials with large enough bandgap to observe physics at room temperature.Directly measuring spin polarized states remains a goal for everyone in the field.

Topological Insulators“Exploration of New Principles in Spintronics Based on Spin Hall Insulators”

Prof. Yoichi AndoOsaka University, Japan

Spin-Filtered

Surface State



7

Topological Insulators: Recent Results

Phys. Rev. Lett. (Sept. 2010)

• Found new TI material: TlBiSe2

• Largest bandgap to date! 0.35 eV

• Room temperature physics possible!

• Most insulating TI materials to date!

• Bulk defects mask surface spin

• Observed surface quantum oscillation

Phys. Rev. B (Dec. 2010)

TlBiSe2

ARPES measurement

EG

Prof. Yoichi AndoOsaka Universit



8





• Scaling challenges in terms of both devicephysics and techniques to produce ultra-low

dimensions• Cost of production and improving device

performance for economical devices



Activelytunablemetamaterials

Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



9


Metamaterials offer potential for synthetic materials with programmable properties. Manytheoretical predictions exist. Materials with real-time tunable properties can be realized.

New Science: Design tunable complex permittivity/permeability leveraging expertise in plasma physics asa function of applied voltage, pressure, gas, etc. RF band-structure properties unknown.

Actively Tunable Metamaterials“Plasma Metamaterials for Arbitrary Complex-Amplitude Wave Filters”

Prof. Osamu SakaiKyoto University

• Arrays formed by micro-cavity plasmasand double helical plasmas onmicrostrip waveguides

• Tune real and imaginary portions ofpermittivity by changing voltage andgas pressure/composition

• Control amplitude and phaseindependently by switching periodicity

• Demonstrated band-pass and phase-delay tunability in X-band range

• Materials can be flexible andaccommodate multi-input/output

• Applications include band-pass/stopfilters, arbitrary complex-valueconverters, phase-shifters

microplasma array

double-helix



10

Actively Tunable Metamaterials“Plasma Metamaterials for Arbitrary Complex-Amplitude Wave Filters”

• Directly tunable permittivity viavoltage and gas pressure/composition

• Tunable in µ-second regime

n)/ (1

11m

2

2

pe

j

double-helix index plasma permittivity

-0.10 -0.05 0.00 0.05 0.10 0.15

-0.05

0.00

0.05

0.10

0.15

0.20

4

3

2

1

Im

(S21)

Re(S21

)

~10 µs

~2 µs

S21

-10 -5 0 5 100

5

10

15

Ar at 5 Torr

Ar at 50 Torr

Ar at 200 Torr

n e

1x1011

cm-3

2x1011

cm-3

5x1011

cm-3

1x1012

cm-3

2x1012

cm-3

5x1012

cm-3

1x1013

cm-3

2x1013

cm-3

5x10

13

cm

-3

Im()

Re()

He at 760 Torr

Ar: 50Torr

Ar: 5Torr

Im(ε)

Re(ε)

Ar: 760Torr

He: 760Torr

ne (cm-3)

low

high



11






• Cost of production and improving deviceperformance for economical devices




Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



12

Bio-Inspired Nanostructures

Prof. UraokaNAIST, Nara Japan

• Use supramolecular protein toself assemble nanostructures

• Uniform dimensions

• Low-temperature process

• Low-cost and easy process

• Can be functionalized for site

selectivity (Ag, Ti, Si)• Ferritin can be used to

incorporate Fe, Ni, and Co

• Core size controllable

“New Functional Devices Using Bio-Nano Process”

DNA RNA polymerase

Ribosome

mRNA Polypeptide

Protein

FoldingAssembly

Supramolecular protein

φ 12 nm

Ferritin

φ 7 nm


Top down lithography approaches limited at extremely small scales. Combination of bottom-up and top-down is required for next-generation devices.

New Science: Design new materials using biological self-assembly processes.



13

Bio-Layer-By-Layer Method

nano-particle 1

binding

mineralization

binding

nano-particle 2

bindingprotein

• Method of stacking supramolecular proteinsto form advanced multi-layer structures

• Can be site-selective

• Can use a bio-mineralization process fordielectric formation



14

Fabrication of MOS Capacitor

Bio-LBL SiO2 PECVD

deposition

Ti electrode

deposition

20 nm SiO2

3 nm SiO2

Anneal in N2

removes ferritincobalt remains

BND layer

p-Si(100)

Ti

Al

Bio-LBL Capacitor!



15

C -V characteristics of MOS capacitors

With cobalt nanodot arraysWithout cobalt nanodot arrays

-10 0 100

0.4

0.8

1.2

Normalized Ca

pacitance (V)

Bias Voltage (V)

Ni CoFe

Charge injected into nanodots

• Demonstration of device potential

• More complex heterostructures

possible!



16


•For physics and electronics, CSWAP (Cost, Size,Weight, and Power) is a continuous challenge








Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



17

[µm]

[ 5 nm]

ZnO Thin Film Transistors

Prof. Yukihara UraokaNAIST, Nara, Japan

• Orbital symmetry makes carriertransport properties robust inpresence of disorder/defects

• Large bandgap (3.4 eV) – Transparent,high breakdown

• Compatible with printable, flexible,large area processing

• Cheap and abundant

• High-performance thin film deviceswith large range of applications

“Unique Degradation Phenomena under Dynamically Stressed IGZO TFTs”


Due to electronic orbital properties of ZnO materials, low-cost electronic devices can befabricated on almost any surface with very high performance

New Science: The exact nature of the carrier transport at the grain boundaries in these devices is stillbeing studied. Physical causes of degradation and instabilities are also unknown.



18

100 ns

500 nsVg pulse

Vmax

Vmin

Vg pulse

Vmax

Vmin 100 ns

500 ns

-20 -10 0 10 2010

-14

10-12

10-10

10-8

10-6

10-4

Dra

in Current [A

]

Gate Voltage [V]

Before110100100010000

Stress time (s)

-20 -10 0 10 2010

-14

10-12

10-10

10-8

10-6

10-4

Dra

in Current [A

]

Gate Voltage [V]

Before110100100010000

Stress time (s)

Falling edge of the pulse accelerates degradation

TFT Electrical CharacterizationTransition Time Dependence



19

Initial Switching to＋Vg Switching to－Vg

Metal

IGZO

DS

Channel E C E C

DS

Channel

DS

Channel E C

Glass sub.

S

G

D

Gate Insulator

TFT Reliability PhysicsHigh-Energy-Electron Defect Formation

• Switch from +Vg -Vg: electrons gain higher energy andcreate defects at interfaces

• SIMS measurements show H decrease after stress; hotelectrons could interact with defect-passivating H and release it



20










Bio-inspired

nanostructures

ZnO TFTs

UF Reliability

MURI

Projects



21

“A 21st Century Approach to Reliability”

Prof. Mark LawU. of Florida, Gainesville

University of Florida Reliability MURI


Device reliability remains a critical issue for all DoD applications. Physical understandingand lifetime prediction are notoriously difficult.

New Science: New integrating models are being built to incorporate materials physics, E/M, carriertransport which are material independent. New nondestructive noise measurementtechniques can yield information about trap energy level and spatial location.

EA = 2.0 eV

EA = ?

*2007 Mantech. Singhal, et al. Nitronex

• Device reliability historically isan ENGINEERING approach

• NOT GOOD ENOUGH!

• We require ability to PREDICTbased on FUNDAMENTALPHYSICS

• UF approach uses object-oriented simulator to integratetheory and experiment

• Developing interesting low-frequency noise

characterization technique

D f i i



22

Defect spectroscopy using noise

• 1/f noise is an indicator ofinterface quality and defects

• Lorentzian noise is anexcellent point defect probe

• Non-destructive technique

• Sensitive to pre- and post-stress measurements

• Applicable to all devices

• Early predictor for reliability:Large changes in noise areobserved even for modeststress test conditions

“A 21st Century Approach to Reliability”

Prof. Gijs BosmanU. of Florida, Gainesville



23

Recent Transitions

• Metamaterials Program – AFRL/RX (Thorp, Urbas) – Plasma metamaterials; Kyoto University, Japan

– Nonlinear optical pulsed controlled metamaterials; IIT Kanpur, India

– Slow-wave metamaterials; Royal Institute of Technology, Sweden

– Electrically tunable; Macquarie University, RMIT; Australia

– Fiber Optic metamaterials; University of Sydney; Australia

– Microwave absorbers; Nanyang Tech.; Singapore

• Nano-bio processing – AFRL/RX (Grote)

– New device fabrication techniques; NAIST, Nara, Japan

• WBG pulsed CL – DARPA/MTO (Albrecht)

– Advanced materials characterization physics, Tohoku U., Japan

AOARD Discoveries Supported by Others

T f ti l O t iti



24

Transformational Opportunities

http://farm1.static.flickr.com/51/143833998_bc7dd42e4c.jpg

http://s849.photobucket.com/albums/ab51/apigee/?action=view&current=flickr-photo-map-world.png

http://uwnews.org/photos.asp?articleID=37724&spid=37725

http://www.garagesalepreview.com/ifixit-completes-early-teardown-of-iphone-4/

Low-Cost

Electronics

Crowd-sourcing

„Internet of Things‟

Composite Data

Reconstruct Environment

Humans as Sensors

Ubiquitous Sensing Paradigm Shift

AOARD Physics & Electronics



25

AOARD Physics & ElectronicsSummary

• AOARD Physics & Electronics Strategy:

– Focus on challenges outlined in TD mission statements suchas CTCs and Layered Sensing vision

– Seeks to exploit transformational opportunities

• Current Areas Discussed:– Enabling Physics and Materials: Topological Insulators

– Actively Tunable Metamaterials: Plasma based

– Low Cost Devices and Integration Techniques: Bio-nano, ZnO

– Reliability: ZnO, MURI

• New opportunities observed for „low-grade‟ electronics

• Portfolio always adapts to new opportunities

AOARD Physics & Electronics



26

AOARD Physics & ElectronicsSummary

Thank You!Questions?

Documents

3. Jessen - AOARD Physics