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MBE GROWTH AND INSTRUMENTATION

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. MBE GROWTH AND INSTRUMENTATION. MBE growth. RHEED. Research Method. References. MBE Growth. Introduction.

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MBE GROWTH AND INSTRUMENTATION

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  1. 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

  2. MBE GROWTH AND INSTRUMENTATION • MBE growth. • RHEED. • Research Method. • References

  3. MBE Growth • Introduction. • Description of MBE system and functioning. • Advantages and applications.

  4. MBE GROWTH-INTRODUCTION Schematic illustration of basic evaporation process for MBE

  5. MBE GROWTHDESCRIPTION AND FUNCTIONING Schematic cross section of an advanced three- chamber UHV system designed for MBE growth

  6. MBE GROWTH APPLICATIONS AND ADVANTAGES • 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.

  7. RHEED - INTRODUCTION • 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.

  8. RHEED PRINCIPLE OF OPERATION RHEED Gun setup for MBE growth

  9. RHEED - OSCILLATIONS Video tape stills of Sn-modified Rheed patterns from As-stabilized (001) GaAs at 550oC: (a) Without Ga flux (b) Immediately after applying Ga flux.

  10. RHEED OSCILLATIONS PLOT Recorder traces of intensity as a function of time at the point A

  11. RHEED – INTENSITY VARIATIONS Illustration of RHEED spot oscillations during the growth of a monolayer

  12. RHEED PATTERNS – AN EXAMPLE 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 )

  13. MBE – RESEARCH METHOD • Experimental. • Video RHEED Intensity Measurement System. • LabVIEW, frame grabber cards. • Specview. • Spectramass PC2000.

  14. MBE - REFERENCES • 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. 11-171-210. • 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/mbechapter

  15. QUESTIONS???

  16. Thank you…..

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