The Nitride Crystal Growth Laboratory: Development and Plans Talks PDF/Fini talk.pdf ·...
Transcript of The Nitride Crystal Growth Laboratory: Development and Plans Talks PDF/Fini talk.pdf ·...
The Nitride Crystal Growth Laboratory:Development and Plans
Paul T. FiniLead Researcher,
Nitride Crystal Growth Laboratory
Univ. of California, Santa BarbaraMaterials Department
Introduction
• Long-term goals of the Nitride Crystal Growth Laboratory include:
• ~340 nm LED/VCSEL to drive phosphors for white lighting
• ~280 nm LED/LD for remote bio-agent detection
• High-efficiency blue or green RC-LED for color mixing
• Truly bulk GaN substrates for light emitters with λ > 365 nm
• Truly bulk AlN substrates for light emitters with λ < 365 nm
Introduction (cont.)
• The Nitride Crystal Growth Laboratory was planned and built for three crystal growth techniques:
• MOCVD (Metalorganic Chemical Vapor Deposition)• Heterostructures: nanometer-level thickness control• Light-emitting (Al,In)GaN device structures
• HVPE (Hydride Vapor Phase Epitaxy)• Fast (> 100 µm/hr) growth rate• Free-standing (t > 200-300 µm) 2” GaN and AlN
• Ammonothermal Growth• Goal: truly bulk (1-2” φ) GaN and AlN single crystals
Growth Technique Interdependence
MOCVD
HVPE AMMONO
Low T
DD templa
tes, L
EO
Free
-stan
ding s
ubstr
ates
Bulk GaN or AlN substrate
Pure nutrient, seed on substrate
Bulk GaN or AlN substrate
Pure nutrient, free-standing seeds
Ammonothermal Growth of Bulk GaN
Milestones:1. Confirmation of fluid transport
growth2. Larger crystals3. Higher cyrstal quality
Growth mechanisms:1. Dissolution of nutrient into
supercritical ammonia2. Transport of Ga*N* up to the
seed crystal(s)3. Precipitation of GaN on the
seed(s)
Lab Layout
Laboratory Construction
Laboratory Construction (cont.)
Laboratory Construction (cont.)
Laboratory Construction (cont.)
HVPE results: C-plane GaN
AFM (z: 5nm scale)
RT PL
Present Status and Near-Term Goals
• MOCVD: GaN:Si, GaN:Mg, InGaN, AlGaN, AlN demonstratedØGrowth of high-quality AlN on sapphireØGrowth of AlN/GaN DBRs for RC-LED structures
• HVPE: thick c- and a-GaN films on sapphire demonstratedØOptimization of conditions for planar a-plane GaNØUse of buffer layers for strain (i.e. cracking) controlØOne-step lateral epitaxial overgrowth (LEO)
• Ammonothermal: small-scale autoclaves used for studies of mineralizer chemistryØLarger autoclave and containment cell being installedØ Seeded growth using various mineralizers
Personnel
• MOCVD growth, characterization:John Kaeding, Rajat Sharma, Amy Hanlon
• HVPE growth, characterization:Ben Haskell, Shigemasa Matsuda
• Ammonothermal synthesis:Tadao Hashimoto, Kenji Fujito
• VCSEL process development, Laser lift-off:Morgan Pattison, Tal Margalith, Kenji Fujito, Tetsuo Fujii
• AlN sublimation growth (planned):Edward Letts, Troy Baker