Ultra-high Barrier Plastic MSE5420 Flexible Electronics Martin Yan, GE Global Research
Ultra-high Barrier PlasticMSE5420 Flexible ElectronicsMartin Yan, GE Global Research
Outline
• Introduction to plastic substrate and need for barrier
•Barrier technologies
•WVTR measurement technologies
•Summary
2 /September 30th, 2008
3 /September 30th, 2008
Source: Displaybank’s presentation on 2007 Flexible Display & Microelectronics Conference
Evolution of Display Technology
4 /September 30th, 2008
OLED Technology
Cathode
n-layer
p-layer
Anode
Light
Sony XEL-1 11” OLED TV
DZ7086 OLED watch by Diesel
iRiver SPINN A/V Player
Nokia Prism Mobile Phone
Kodak EasyShare LS633 Camera
5 /September 30th, 2008
Flexible OLED Display
Source: UDC presentation on 2007 Flexible Display & Microelectronics Conference
6 /September 30th, 2008
Replace Glass with Plastic Substrate
NOW
Glass Substrate
Plastic Advantages
• Rugged.• Thinner.• Lighter.• Enable flexible display.• Enable R2R processing.
FUTURE
“Roll-Up Displays”
Plastic Film Substrate
Energy Consumption for Lighting: Year 200122% of the total electricity generated in the U.S. was used for lighting!
Total U.S. Primary Energy Consumption for Lighting by Sector
Lighting Energy Consumption by Sector & Source
Source: U.S. Lighting Market Characterization Volume I:
7 /September 30th, 2008
Need to replace incandescent with more efficient light technology!
8 /September 30th, 2008
Organic Electronics (OE) Advanced Technology Program at GE Global Research
Technologies:
Flexible substrate
Transparent contact
Metal contactV Organic Active Layers
“Newspaper-Like”Roll-to-Roll Fabrication
V• OLED Devices• Low Cost Manufacturing• High Barrier Substrate
High barrier substrate enables R2R OLED manufacturing.
9 /September 30th, 2008
OLED Offers Novel FeaturesMechanical Flexibility Thin and Light Transparent
Color Tunability
10 /September 30th, 2008
Source: Polymer Vision’s presentation on 5th Flexible Display and Microelectronics Conference
Source: UDC’s presentation on 5th Flexible Display and Microelectronics Conference
UDC’s Flexible Display Concept Polymer Vision’s Flexible Display Concept
GE’s Flexible Lighting Concept
Flexible OLED Product Concepts
Source: Best Life Magazine – February 2006
11 /September 30th, 2008
Opportunity for Plastic Substrate
•Flex.Display- OLED- LCD
•Digital Paper- E-paper- Postage
•Lighting- General lighting- Back lighting
•Solar Cell (PV)- Thin Film PV
Barrier Plastic Film
Maj
or P
laye
rs
Challenges for Flexible OLED SubstrateThe Problem
OLED
Polymeric substrate
Transparent electrode
H2O O2Commercial available polymeric substrate
12 /September 30th, 2008
Transparent ConductorMoisture/Oxygen Permeability
Hole InjectorLight Emitting Polymer
Metal Cathode
Ultra High Barrier
Ultra High Barrier
Transparent Anode
Moisture OxygenLow Temp.
PlasticHigh Temp.
Polycarbonate
Low Conductivity,Low Transmission
Anode
High Conductivity,High Transmission
Anode
Thermo-mechanical stability Optical Transmission
CTE Reduction / Stress Balance
CTE Reduction / Stress Balance
High CTE Plastic
H2Olow 10-6 g/m2/day
O2< 10-3 cc/m2/day
13 /September 30th, 2008
< 40 Ohm/ sq> 90 %T
Shrinkage< 20 ppm/hr @150°CBendingdiameter <=1”Adhesion≥ 4B
Light Emitting PolymerMetal Cathode
Ultra High Barrier
Ultra High Barrier
Transparent AnodeHole Injector
Substrate Requirement- Key Properties
> 80 %T
Barrier Substrate Development at GE Global Research
Plastic Substrate
Film
Ultra-high Barrier Coating
Chemical Resistant Coating
Transparent Conductor
Coating
Technology Development at GE
Enable
Integrated Plastic OLED Substrate
14 /September 30th, 2008
Chem resist layer
High heat polycarbonate
Graded ultra high barrier
Chem resist layer
Transparent electrode
Outline
• Introduction to plastic substrate and need for barrier
•Barrier technologies
•WVTR measurement technologies
•Summary
15 /September 30th, 2008
16 /September 30th, 2008
Material Options for Transparent Hermetic Barrier
Moisture Permeability
Time to Reach 50% of Outside RH
Ref. Traeger
Log
Thic
knes
s (m
eter
s)
OTR through Perfect SiO2 Barrier:
10nm ⇒ 10-24 cc/m2/day
10 nm continuous glass-like coatings would exceed the needs
17 /September 30th, 2008
Defect-Driven Moisture Permeation
1 10 100 1000
0.01
0.1
1
10
100
1000 Uncoated
OTR
@ 2
50 @ 1
00%
O2
SiNx Thickness (nm)
Detection limit
Non-Fickian Diffusion ~ 100 defects/mm2
20x
~1mm
Defect Imaging w/ Acetone
Barrier performance of single layer inorganic coating is defect limited
18 /September 30th, 2008
Ultra-high Barrier: Single Layer Approach–Uni. Of Colorado: Atomic Layer
Deposition of AlOx
–Dow Corning: Plasma Enhanced Chemical Vapor Deposition of SiOxCy
–Symmorphix: Sputtering of AlSixOy
Source: Symmorphix’s presentation on 4th
Flexible Display and Microelectronics Conference
19 /September 30th, 2008
Ultra-high Barrier: Multilayered Approach
Concept for Multilayer UHB
Tens of µm
Hundreds of nmOrganic coating
Inorganic coating
Defects
Source: VITEX’s presentation on 5th Flexible Display and Microelectronics Conference
Permeation Simulation: Multilayered Barrier
20 /September 30th, 2008
Assumptions: - 2 perfect barriers- each barrier has 1 defect- defects are offset/decoupled
Low
High
Fick’s Law:
Continuity:
DiffusionEquation:
0.1 1 10
0.1
1
ConductionLimitedRegime
Flux
Rat
io
Distance/Offset
Offset
Distance
Flux Ratio =Flux2 Layer System
Flux 1Barrier System
Work in this regime toachieve Ultra-High Barrier
21 /September 30th, 2008
Ultra-high Barrier: Graded Approach
XPS Spectrum of Graded UHBGE’s Graded Ultra High Barrier
Inorganic Organiczone
Continuous composition transition
Cross-sectional TEM of Graded UHB
22 /September 30th, 2008
Graded Ultra-high Barrier Plastic Film
Parallel plate PECVD High T Lexan® film
Low temperature PECVD process is compatible with plastic substrates
Base Film Surface Quality is Critical
23 /September 30th, 2008
Flexible OLED substrateThe Problem
OLED
Polymeric substrate
Transparent electrode
H2O O2Commercial available polymeric substrate
3,530 hrs at 23°C 40%RH
The Solution
24 /September 30th, 2008
OLED
Chem resist layer
High heat polycarbonate
Graded ultra high barrier
Chem resist layer
Transparent electrode
GE Barrier Substrate
H2O O212 mm
Proved that high barrier substrate is possible
Key USDC Specifications* GEGR Performance• Moisture Barrier 10-6 g/m2/day low 10-5~mid 10-6 (at 23°C 50 % RH)• Chemical Resistance acid, solvent, alkali Pass• Electrical Conductivity ≤40 Ω/Sq 40.3 Ω/Sq• Optical Transparency >80% 82 %• Mechanical Flexibility bend around 1” radius Pass.• Thermo-Mechanical Stability 2000C for 1hour Pass • Adhesion ≥4B 4B• Dimension stability <20 ppm/hr at 150°C 4 ppm/hr• Average surface roughness <5 nm 0.6 nm
15 cm square flexible OLED lighting Device on high heat polycarbonate substratewith graded UHB
GE’s Graded Barrier Plastic Performance
* Subset of complete USDC specification list
25 /September 30th, 2008
Outline
• Introduction to plastic substrate and need for barrier
•Barrier technologies
•WVTR measurement technologies
•Summary
26 /September 30th, 2008
WVTR measurement technologies
• Capacitive or Resistive (humidity sensor)
• Spectroscopy (mass spectroscopy, fluorescence quenching)
• Calcium degradation (optically or change in resistance)
• Radioactive (tritium)
27 /September 30th, 2008
Commercially Available Gas Permeation Measurement
H2O or O2H2O or O2
H2O or O2
Fourier transform Infrared (FTIR) Spectrometer
Source: PERMATRAN-W® Model 3/33 Operator’s Manual
28 /September 30th, 2008
Detection limit for H2O: 5×10-3 g/m2/day
29 /September 30th, 2008
Calcium Corrosion Test: GE’s Setups
Ca test @ 23°C / 50%RH
Ca Test @ 60°C 90% RH
Polycarbonate
EpoxyCa
Barrier Coating
Glass
525 hrs90% O.D.
Initial100% O.D.
Detection limit for H2O: 1×10-5 g/m2/day
30 /September 30th, 2008
General Atomics Tritium Test
Tritium Test: GAT’s Setup
Source: RALF DUNKEL, ROKO BUJAS, ANDRE KLEIN, AND VOLKER HORNDT, PROCEEDINGS OF THE IEEE, VOL. 93, NO. 8, AUGUST 2005, pg 1478-1482
Detection limit for H2O: 2×10-7 g/m2/day
31 /September 30th, 2008
OLED Device Test
Universal Display CorporationOLED Shelf Lifetime Test @ 60°C 85% RH
Glass/Glass control Device on GE sample
Glass/Glass control Device on GE sample
w/ desiccantw/o desiccant
Source: GE’s presentation on 4th Flexible Display and Microelectronics Conference