Transcript Silicon Quantum Dots: Grown by Ion Implantation and annealing

Silicon Quantum Dots: Grown
by Ion Implantation and
annealing
By
Mary Coan
Outline
• History of Silicon quantum dots
– How they were made
• Properties of Silicon Quantum Dots grown
by ion implantation and annealing
• Advantages/Disadvantages
• Different methods to grow Silicon
Quantum Dots
– Which method is the best?
• Summary
History of Si QDs
• 1960’s: First quantum size effects were
seen in semiconductor nanocrystals
• 1970’s: Louis Brus was working in Bell
Labs researching colloidal synthesizes
• 1980’s: First semiconductor quantum dots
were grown
• 1990: First visible-photoluminescence
seen from Si QDs
History of Si QDs
• 1993: Silicon optoelectronic integrated
circuit is suggested
• 1993 to present: Si Quantum dots have
been extensively researched
– Different fabrication methods
•
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microwave plasma decomposition of SiH4
laser breakdown of SiH4
plasma-enhanced chemical vapor deposition
high frequency discharge
high dose ion implantation
Formation of Si QDs: Ion
implantation and annealing
T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Vacuum 81, 179 (2006).
Properties of Si QDs
• Photoluminescence
– Peak energy and intensity
• Size ranges from 1 nm to over 10 nm in
diameter
• Size distribution within host material
Photoluminescence
C.W. White, J.D. Budai, S.P. Withrow, J.G. Zhu and S.J. Pennycock, IEEE
Conference Proceeding 824 (1996).
Photoluminescence
T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Vacuum 81, 179 (2006).
Photoluminescence
T.S. Iwayama, T. Hama, D.E. Hole, I.W.
Boyd, Vacuum 81, 179 (2006).
Suggested Mechanisms
T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Solid-State Electronics 45, 1487 (2001).
Suggested Mechanisms
R. Krishnan, UR, (2005).
Range of Sizes
• Longer anneals = Larger Si QDs
– Ostwald Ripening
T.S. Iwayama, T. Hama, D.E. Hole, I.W. Boyd, Vacuum 81, 179 (2006).
Size distribution within Host Material
M.L. Brongersma, A. Polman, K.S. Min, H.A.
Atwater, “J. Appl. Phys. 86, 759 (1999).
Defects within Host
C. J. Nicklaw, M. P. Pagey, S. T. Pantelides, D. M. Fleetwood, R. D. Schrimpf, K. F.
Galloway, J. E. Wittig, B. M. Howard, E. Taw, W. H. McNeil, J. F. Conley, Jr., IEEE Trans.
Nucl. Science 47, 2269 (2000).
Defects within Host
C. J. Nicklaw, M. P. Pagey, S. T. Pantelides, D. M. Fleetwood, R. D. Schrimpf, K. F.
Galloway, J. E. Wittig, B. M. Howard, E. Taw, W. H. McNeil, J. F. Conley, Jr., IEEE Trans.
Nucl. Science 47, 2269 (2000).
Defects within Host
C. J. Nicklaw, M. P. Pagey, S. T. Pantelides, D. M. Fleetwood, R. D. Schrimpf, K. F.
Galloway, J. E. Wittig, B. M. Howard, E. Taw, W. H. McNeil, J. F. Conley, Jr., IEEE Trans.
Nucl. Science 47, 2269 (2000).
Advantages/Disadvantages
• Advantages:
– Ease of integration into silicon based
microelectronics (Dots and Process)
– Ability to control the PL intensity and peak
energy
• Disadvantages:
– Large size distribution within host material
– Defects within host material
– Surface damage (QDs)
Other Fabrication Techniques
• Microwave Plasma Decomposition of
Silane Gas
• Laser breakdown of Silane Gas
• Plasma Enhanced Chemical Vapor
Deposition
• High Frequency Spark Discharge
• Colloidal
Which Method is Best?
• It depends on what you want to use the
Silicon QDs for.
• If you want to make an optoelectical
integrated circuit:
– Plasma Enhanced CVD
– Ion Implantation
• If you want some cool flourishing Si QDs:
– Colloidal
Summary
• Properties of Si QDs were discussed
– PL dependent on:
• Anneal time, temperature and process
• Ion dose
• Defects caused by Ion Implantation
– Quantum dot surface\host material
• Causing lower luminescence intensity
– A Large size distribution throughout the Host
• In the past this was a good technique now
it is outdated by PCVD
Questions ??