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AVAILABLE
TECHNOLOGIES |
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High
Quality GaN Films on Silicon Substrates Using HfN Buffer Layers
IB-1800
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APPLICATIONS
OF TECHNOLOGY:
- Transistors
- Solar
cells
- Photodetectors
operating in the ultraviolet to green portion of the spectrum
- Resonant
tunneling devices
- Blue
and white light emitting diodes
- Laser
diodes
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ADVANTAGES
OVER GALLIUM NITRIDE GROWN DIRECTLY ON SILICON SUBSTRATES:
- Improved
luminescence
- Fewer
crystal defects
ADVANTAGES
OVER GALLIUM NITRIDE GROWN ON SILICON WITH ALUMINUM NITRIDE
BUFFER LAYERS:
- Superior diffusion resistance
- Closer lattice match with gallium nitride
- Metallic conductivity
- Mirror reflectivity
ADVANTAGES
OVER GALLIUM NITRIDE GROWN ON SAPPHIRE OR SILICON CARBIDE:
- Larger wafer diameter
- Less expensive substrate wafers
- Better substrate thermal conductivity
- Compatibility with Si device technology
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ABSTRACT:
Eicke Weber and colleagues at Berkeley Lab have grown gallium nitride films
of excellent structural and optical quality on silicon substrates
using a hafnium nitride (HfN) intermediate layer. The researchers
have established the process parameters for the deposition
of HfN on silicon as well as gallium nitride on HfN.
Growing gallium nitride on a silicon rather than a sapphire
substrate offers considerable cost advantages and the possibility
of monolithic integration of GaN-based devices with conventional
Si electronics. However, growing GaN directly on silicon usually
poses cracking and wetting problems. While these problems
have been mitigated using aluminum nitride (AlN) buffer layers,
AlN exacerbates interdiffusion at the surface. Because Si
is a n-type dopant, this interdiffusion results in high unintentional
doping levels in the film and the device area. Using novel
diffusion-resistant HfN buffer layers on silicon, Robert Armitage
and Eicke Weber have grown GaN films up to 1.2 µm thick
with properties comparable to those grown on AlN buffers on
silicon. Even better results are expected when the GaN deposition
temperature and the HfN film deposition parameters are optimized.
Additional advantages of the Berkeley Lab buffer material
include a closer lattice match with gallium nitride, metallic
conductivity, and mirror reflectivity.
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STATUS:
- U.S. Patent #6,929,867 and other patents pending
- Available for licensing
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REFERENCE
NUMBER: IB-1800
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SEE
THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
- Growth of GaN with a Low Density of Structural
Defects, IB-1619
- Improved GaN MBE-Growth using Bismuth as a
Surfactant, IB-1290
- Novel GaN Thin Film Growth Procedure on Lattice Mismatched
Substrates, IB-1461
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PUBLICATION:
Armitage, R.,
Yang, Q., Feick, H., Gebauer, J., Weber, E. R., "Lattice-Matched
HfN Buffer Layers for Epitaxy of GaN on Si," Applied
Physics Letters 2002, 81, 1450-1452
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CONTACT:
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Technology
Transfer Department
E.O. Lawrence Berkeley National Laboratory
MS 90-1070
Berkeley, CA 94720
(510) 486-6467 FAX: (510) 486-6457
TTD@lbl.gov |
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