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MBE GROWTH AND INSTRUMENTATION
Thesis Proposal Outline for the Degree of
Master of Science
Major Professor
Dr. Terry Golding Ph.D,
University of North Texas
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MBE GROWTH AND INSTRUMENTATION
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MBE growth.
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RHEED.
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Research Method.
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References
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MBE Growth
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Introduction.
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Description of MBE system and functioning.
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Advantages and applications.
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MBE GROWTH-INTRODUCTION
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Schematic illustration of basic evaporation process for MBE
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MBE GROWTH
DESCRIPTION AND FUNCTIONING
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Schematic cross section of an advanced three- chamber UHV
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APPLICATIONS AND ADVANTAGES
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Growth of electronic and photonic devices such as solar
cells, diode lasers, LEDs and heterojunction bi-polar
junction transistor.
Slow growth rate of ~1μm.
Reduced temperatures of about 500-600oC
Reduced handling requirements of toxic materials such as
As.
The ability to abruptly cease or initiate molecular beams
producing hyperabrupt surfaces.
Facility of in situ analysis during growth.
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RHEED - INTRODUCTION
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Powerful tool for in situ analysis during the growth
process.
Used to calibrate growth rates.
Observe removal of oxides from the substrate.
Calibrate the substrate temperature.
Monitor the arrangement of surface atoms.
Give a beedback on surface morphology.
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RHEED
PRINCIPLE OF OPERATION
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RHEED Gun setup for MBE growth
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RHEED - OSCILLATIONS
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Video tape stills of Sn-modified Rheed patterns from Asstabilized (001) GaAs at 550oC: (a) Without Ga flux (b)
Immediately after applying Ga flux.
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RHEED OSCILLATIONS PLOT
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Recorder traces of intensity as a function of time at the
point A
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RHEED – INTENSITY VARIATIONS
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Illustration of RHEED spot oscillations during the
growth of a monolayer
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RHEED PATTERNS – AN EXAMPLE
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RHEED patterns and the corresponding electron micrographs of (110) GaAs
grown using MBE : (a) GaAs heated in vaccum to 580oC for 5min. (b) 150oA layer
of GaAS on the surface of (a). (c) 1µm of GaAs deposited on surface of (a )
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MBE – RESEARCH METHOD
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Experimental.
Video RHEED Intensity Measurement System.
LabVIEW, frame grabber cards.
Specview.
Spectramass PC2000.
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MBE - REFERENCES
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Oscillations in the Surface Structure of Sn-doped GaAs during growth
by MBE [Surf. Sci. 103, L90 (1981)] by J.J.Harris, B.A.Joyce and
P.J.Dobson.
A.Y.Cho, J. Vac. Sci. Technol. 8, S31 (1971).
Molecular Beam Epitaxy of III-V Compounds: Technology and
Grwoth Process, by Klaus Proog. Ann. Rev. Material Sci. 1981. 11171-210.
W.Braun. Applied RHEED. Reflection High-energy Electron,
Diffraction during Crystal Growth. 1999. Springer Tracts in Modern
Physics, 154. 2.
A. Y. Cho, Key papers in Applied Physics – Molecular Bem Epitaxy,
AIP Press 1999.
http://mrlxp2.mrl.uiuc.edu/~rheed/index.html
http://www.ece.utexas.edu/projects/ece/mrc/groups/street_mbe/mbecha
pter
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QUESTIONS???
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Thank you…..
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