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A presentation given at the Lockheed-Martin Advanced Technology Center in Palo Alto, CA
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Lockheed-‐Martin Advanced Technology Center J. Michael Pinneo, Ph.D., J.D.
September 24, 2009
1 J. Michael Pinneo, [email protected]
Survey
! I. Diamond synthesis and properties
! II. Aerospace applications
2 J. Michael Pinneo, [email protected]
CVD Diamond -‐ Synthesis ! Overall chemistry: deposition occurs in diamond metastability region, graphite stability region ! i. CxHy + H0 ! Cg+ Cd (mostly graphite) ! ii. Cg + H0 !!! CxHy ! iii. Cd + H0 -‐> CxHy (~1/400 ii.)
! Yields poly-‐ and single-‐crystal
3 J. Michael Pinneo, [email protected]
CVD Diamond – Synthesis Methods ! Hot filament, plasmas, combustion, ...
4
VHF Plasma, 8”
Combustion, 4” linear
Microwave Plasma, 4”
RF Plasma Torch
DC Plasma Torch
J. Michael Pinneo, [email protected]
CVD Diamond -‐ Varie7es Scale-up ExperienceMicrowave Diamond CVD
30Kw, 915 MHzPlasma ScanningDeposition Diameter 14"Conformal 3-D CapabilityThickness Uniformity <8% over 12"
5
Diamond on Si Wafers
Diamond-‐coated BC wear blocks and Si3N4 ball bearing
Diamond heat spreader prototype for microprocessor
Diamond-‐coated Si3N4 fiber
Diamond-‐coated Si3N4 dome (14” dia x 3.5” deep)
J. Michael Pinneo, [email protected]
CVD Diamond – Thermal Proper7es
! Thermal conductivity @ 273°K: 8 – 25 W/cm-‐°K ! Thermal conductivity peak ~ 77°K: 60 W/cm-‐°K ! Thermal diffusivity: 1.16 cm2/sec ! Thermal conductivity is high even in nanocrystalline films
! Extremely useful in thermal management
6 J. Michael Pinneo, [email protected]
CVD Diamond – Mechanical Proper7es
! Hardness: 10,000 kg/mm2 ! Modulus: 1,100 Gpa ! Poisson’s ratio: ~ 0.06 ! Thermal Expansion Coefficient: ~ 1 x 10-‐6/°C @ 273°K ! Coefficient of sliding friction (µ): 10-‐2 to 10-‐3
! Sonic velocity: ~ 18 km/sec
7 J. Michael Pinneo, [email protected]
CVD Diamond Op7cal Proper7es
! Transparent: 225 nm –> DC ! ~ 5µm – 6µm, intrinsic phonon absorption
! Refractive Index ~ 2.4 ! Emissivity @ 273°K ~ 0.04
8 J. Michael Pinneo, [email protected]
CVD Diamond Electronic Proper7es
! Resistivity, intrinsic: > 1015 Ω-‐cm ! Resistivity, B-‐doped: 10-‐3 Ω-‐cm ! Dielectric constant: 5.7 ! Breakdown field: > 107 V/cm ! P and N dopants: B, B & D plasma
9 J. Michael Pinneo, [email protected]
Aerospace Applica7ons Thermal Management
10 J. Michael Pinneo, [email protected]
Heat Spreaders for Ac7ve Devices
Device
Cold Plate
Diamond Heat Spreader!
K = 12 W/cm-°K
SiC Heat Spreader!
K = 2.5 W/cm-°K
T1
T2
Tr1
Tr2
Trn
Q ∝ (T1 – T2)
Q ∝ 1/(∑ Tr1…Trn)
11 J. Michael Pinneo, [email protected]
Diamond Microprocessor Heat Spreaders
! IR image of processor temperature
! Diamond enabled 1.8x clock rate increase
12
Die Temperaturew/ Copper Spreader
Die Temperaturew/ Diamond Spreader
Copper Heat Spreader Diamond Heat Spreader
J. Michael Pinneo, [email protected]
GaN HEMT
13
5© 2005-2006 Group4 Labs, LLC. All Rights Reserved
!""#$%&'%()*+#"%,+#-./+*+"#-)*/%0+1)2+3%&*%4#56(+*/-,%&'%,+#-%3&7"2+3%)3%(&*/%)*%2&89#")3&*%:)-,%-,+%3+9#"#-)&*%! #*0%:)0-,%&'%-,+%3&7"2+3;
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d
T0 = 23°C
TP
!T = TP–T0
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!"#$%&'(%)*#'(+!$,-!,$#
J. Michael Pinneo, [email protected]
Thermal Management Heat Spreaders, GaN HEMTs
! Attach 100µm diamond heat spreader to GaN device: ! 200% increased power cf. SiC heat spreader;
! 1000% increased power cf. Si heat spreader.
Courtesy Group 4 Labs, and Jonathan Felbinger and Prof. Eastman, Cornell University.
14 J. Michael Pinneo, [email protected]
! 4” free-‐standing GaN wafer on diamond
15
Courtesy Group 4 Labs
J. Michael Pinneo, [email protected]
16 J. Michael Pinneo, [email protected]
Separation between linear sources [µm]
GaN HEMT on Diamond ! Benefits:
! Higher output power ! Lower operating temperature ! Greater device density
! System Impact: ! Radar -‐> increased target acquisition distance ! Active ECM -‐> increased range, effectiveness ! Increased MTBF -‐> reduced maintenance $, time
17 J. Michael Pinneo, [email protected]
Poten7al Applica7on
! F-‐35 thermal issues ! Fuel used as internal systems heat sink ! Low fuel near end of mission:
! Higher fuel temperature ! Lower ∆T in thermal transfer chain ! Increased avionics temperature
18 J. Michael Pinneo, [email protected]
F-‐35 Thermal Issue
! Reduce overall thermal resistance between avionics and fuel ! Apply diamond to thermal transfer path:
! Device level: diamond heat spreaders ! Card/module level: diamond heat pipes & plates ! Heat exchangers: diamond or diamond/SiC composites
19 J. Michael Pinneo, [email protected]
Op7cal Applica7ons
! Important properties ! Broadband transparency
! 225 nm -‐> DC ! Intrinsic phonon absorption ~ 5 µm – 6 µm
! Hardness ! Low loss tangent (< 10-‐4)
20 J. Michael Pinneo, [email protected]
IR Op7cal Applica7ons
Rain/dust impact damage on IR optic (F-‐15E)
21 J. Michael Pinneo, [email protected]
IR Op7cal Applica7ons
! Erosion barrier for ZnS/ZnSe IR optics ! Hardness, IR transparency
! Can’t CVD direct on IR material, but chalcogenide “glue” works.
! AR coatings are available. V
ISIBLE
22 J. Michael Pinneo, [email protected]
Op7cs: High Power Lasers
! Windows/Lenses ! High damage threshold ! Physically robust
! Solid State Lasers ! Increased output ! Reduced module volume
Northrop-‐Grumman 100 Kw laser, Phase 3, JHPSSL
Advanced Tactical Laser (ATL)
23 J. Michael Pinneo, [email protected]
Op7cs: HPM Windows
! DEW: high power microwave windows (HPMW) ! High K, low loss tangent, low TCE ! >1 Gw CW, > 10 Gw pulsed @ 90 GHz ! USAF BAA/Raytheon 2009 win to provide domestic source
! Current vendors: Europe, Asia ! >$100K each
24 J. Michael Pinneo, [email protected]
Mechanical, Fric7on & Wear
! Important properties ! Low friction ! Hardness ! Modulus ! Corrosion resistance
25
F-‐15E Exhaust Flap Mechanism
J. Michael Pinneo, [email protected]
Machining Opera7ons
! Diamond-‐coated tooling Increased tool life Higher machining speeds Better workpiece finish
26
Diamond – coated cutting tools courtesy of Crystallume, Inc.
J. Michael Pinneo, [email protected]
Bearings and Seals
! Good coating and performance increases shown for diamond on Si3N4 ball bearings, BC wear shoes, and SiC pump seals.
! Diamond pump seals in commercial production by Advanced Diamond Technologies, Inc.
27
Diamond-‐coated pump seals, courtesy of Advanced Diamond Technologies, Inc.
J. Michael Pinneo, [email protected]
Diamond as a MEMS Material
! Hardness & Modulus ! Low self-‐adhesion/stiction ! Hydrophobic ! Tolerate aggressive environments
! Surface can be functionalized to provide sensing capability
28 J. Michael Pinneo, [email protected]
Diamond RF MEMS Switch
Diamond for High Power Lasers ! Desirable properties: transparency, K, TCE, damage threshold
! Natural diamond laser demonstrated in 1985(1) ! Optically pumped (Ar ion laser) ! Lasing medium: H3 color center, 530 nm ! Tunable due to coupling with phonon energy levels ! Efficiency 13.5%
! Interesting, but natural diamonds too costly & rare
29
(1) Rand & DeShazer, Optical Letters, 1985 vol. 10 (10) pp. 481-‐483
J. Michael Pinneo, [email protected]
Diamond for High Power Lasers ! What’s changed? ! Large, high quality single crystal diamonds by CVD
! R. Hemley’s group at Carnegie Institute(2)
! Microwave plasma CVD followed by HP or LP anneal ! Highly accessible with relatively simple equipment ! Cost-‐effective technology
30
(2) Recent advances in high-‐growth rate single-‐crystal CVD diamond, Qi Liang, et al., Diamond and Related Materials, 2009 vol. 18 (5-‐8) pp. 698-‐703
J. Michael Pinneo, [email protected]
Diamond for High Power Lasers ! High efficiency diamond Raman laser(3)
! 1.2 watt output @ 573 nm, 532 nm pump ! Conversion efficiency 63.5% ! Slope efficiency 75% ! Peak photon conversion efficiency 91%
! Diode-‐pumped diamond Raman laser shown in 2005(4)
31
(3) Highly efficient diamond Raman laser, Mildren and Sabella, Optics Letters, 2009 vol. 34 (18) pp. 2811-‐2813 (4) Diode pumped diamond Raman microchip laser, Demidovich, et al., Conference on Lasers and Electro-‐Optics (CLEO) Europe, 2005, p. 251
J. Michael Pinneo, [email protected]
Diamond for Hypersonic Flight
! Challenge: extreme aeroheating of vehicle and control surfaces during endoatmospheric flight (≥ 2,500°C) ! Constrains thermal solutions to ablative materials ! Ablatives can substantially depart from nominal aerosurface design during flight
! Impact on vehicles: ! Increased control authority required ! Increased total divert energy needed ! Increases vehicle weight/size, reduces range ! Introduces weather (rain, dust) as launch limitation
! Resolution: robust, nonablative thermal coating
J. Michael Pinneo, [email protected] 32
Diamond for Hypersonic Flight ! Critical info: diamond does not bulk graphitize at T > 2,200°C for hours
! Suggests: Anti-‐oxidation coating + thick diamond film could be useful as a robust, nonablative material for some hypersonic endoatmospheric missions. ! Oxidation barrier: Re/Ir – affordable because < 10µm ! Low diamond TCE – helps maintain antioxidation coating integrity
! Diamond hardness/modulus – better resistance to particle erosion (rain, dust) than ablatives
J. Michael Pinneo, [email protected] 33
The End
34 J. Michael Pinneo, [email protected]