ECE 730 Topic 26 - Molecular Beam Epitaxy and Characterization of Quantum Nanostructures and Devices
Instructor
Prof.
Zbig
Wasilewski
Office:
QNC
4606.
Office
hours:
by
appointment
(via
email)
Email:
zbig.wasilewski@uwaterloo.ca
(Do
not
use
LEARN
email
to
reach
the
instructor)
Description
Well controlled manipulation of material structure at atomic level is now essential in achieving the desirable properties of devices, were they to be electronic, photonic or spintronic in nature. Molecular Beam Epitaxy (MBE) is the most powerful tool for such nanoengineering. The course gives an overview of the principles and capabilities of this extremely versatile technology as well as related characterization techniques. Selected topics, most relevant to the equipment and research at uWaterloo, will be given particular attention.
Course and teaching objectives
This course will help students with no or limited prior background in the field to:
- Acquire a general background and selected specific knowledge in the field of epitaxial technologies with emphasis on MBE, basic theory, applications, challenges, recent developments, etc.
- Identify the critical parameters for the epitaxial structures which should be measured or verified to facilitate success of the subsequent processing and/or experiments.
- Acquire a broad knowledge of the characterization techniques which can provide such information.
- Acquire in-depth understanding and working knowledge of selected advanced characterization techniques particularly relevant to the equipment and research at the University of Waterloo.
- Direct their creativity in the directions compatible with the capabilities of MBE technology, from the fundamental studies to the pursuits of the most advanced devices of the future.
Antirequisites
NANO 701_T002, NANO 702_T003.
Syllabus
-
Introduction
to
crystal
growth
and
epitaxy
(2
hours)
Crystallography ABCs; Crystal growth thermodynamics ABCs; Bulk crustal growth technologies; Epitaxial Technologies -
Focus
on
Molecular
Beam
Epitaxy
(MBE)
(2
hours)
MBE – the ultimate nano-playground and the powerful production tool; sampler of MBE-grown devises (Laser Diodes and Quantum Cascade Lasers, Short-Period-Superlattice Detector Arrays, Quantum Well and Quantum Dot Infrared Photodetectors, High-Efficiency Solar Cells, High Electron Mobility Transistors (HEMTs), Single Photon Sources, Photonic Crystals, MBE for Quantum Computing); Sky is the limit (MBE in outer space, Ultra-High-Mobility 2D Electron Gases) -
MBE
technology
overview
(5
hours)
Ultra-High Vacuum (UHV) why and how; the MBE hardware; Variants of MBE (Gas Source MBE, Metalorganic MBE, Group-IV MBE, Migration-Enhanced MBE, Atomic Layer MBE; Droplet Epitaxy); MBE for key material systems (semiconductors, complex oxides including high Tc superconductors, graphene, nano-magnetics and spintronics, organic multilayers); Towards all-UHV processing (in-situ pattering, vacuum lithography, buried heterostructures); MBE history and current status (World, North America, Canada, University of Waterloo) -
The
Physics
of
MBE
(5
hours)
Basic processes in MBE (surface reconstruction, physisorbed and chemisorbed states, surface diffusion, island nucleation, step-flow, segregation, intermixing, clustering, sublimation), Role of strain (critical thickness, relaxation channels, metamorphic and psedomorphic layers, 2D and 3D growth modes, band structure engineering), Modeling (atomistic models – Kinetic Monte-Carlo, step-flow models, continuum models) -
From
Quantum
Wells
to
Quantum
Wires,
Dots
and
Molecules
–
MBE
for
nanotechnology
(4
hours)
Quantum Wells (well-barrier interfaces, interface roughness, interface scattering, Quantum Wells into Quantum Dots and Quantum Molecules via nanofabrication), Quantum Wires (Au-induced growth of nanowires, self-induced growth of nanowires, metal-free nanowire growth, selective area growth ), Quantum Dots (Stranski-Krastanov, Volmer-Weber, Droplet Epitaxy, selective area), Quantum Molecules, Quantum Dot Superlattices -
In-situ
techniques
for
MBE
growth
monitoring
and
layer
characterization
(3
hours)
Reflection High Energy Electron Diffraction (RHEED) for surface reconstruction, growth mode and growth kinetics, Desorption Mass Spectrometry (DMS) for growth chemistry, Band-edge absorption and pyrometry for temperature monitoring, reflectivity for growth rates and compositions, light scattering, Nanoprobes, Other techniques -
High
Resolution
X-Ray
Diffraction
for
Epitaxial
Structures
(5
hours)
Overview; Reciprocal Space; Analysis of Epitaxial Layers; Simulation of X-ray Diffraction Rocking Curves; Triple-Axis Diffractometry; Separation of lattice tilts and strains; Full reciprocal space mapping and applications; Interface Roughness Metrology -
Chemical
and
Physical
Characterization
of
Epitaxial
Structures
(4
hours)
Transmission Electron Microscopy (TEM); Atom Probe Tomography (APT); Scanning Electron Microscopy (SEM); Cathodoluminescence (CL); Electron Beam Induced Current (EBIC); Auger Electron Spectroscopy (AES); Secondary Ion Mass Spectrometry (SIMS); Rutherford Backscattering Spectrometry (RBS) -
Optical
Characterization
of
Epitaxial
Structures
(4
hours)
Dark-Field, Phase, and Interference Contrast Microscopy; Interferometric Microscopy; Defect Etches; Ellipsometry; Transmission; Reflection; Transmission Matrix Method for multilayer structures, Contactless Electro Reflectance; Light Scattering; Photoluminescence (PL); Raman Spectroscopy -
Characterization
of
Epitaxial
Structures
–
probing
minority
and
majority
carriers
(2
hours)
Hall Effect, Spreading Resistance, Contactless Carrier density and Mobility, Generation-Recombination Statistics; Deep-Level Transient Spectroscopy (DLTS), Time-of-Flight Drift Mobility, Recombination Lifetime/Surface Recombination Velocity; Photoconductance Decay (PCD), Photoluminescence Decay (PLD), Electron Beam Induced Current (EBIC), Capacitance-Voltage (C-V) profiling
Textbook
No textbook required. Lecture notes and handouts will be provided.
General references
- “Molecular Beam Epitaxy. From Research to Mass Production”, Edited by Mohamed Henini, Elsevier (2013).
- “Molecular Beam Epitaxy. Applications to Key Materials” , Edited by R.F.C. Farrow, William Andrew Publishing (1995)
- “Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics”, Edited by Mohamed Henini, Elsevier (2008)
- “Self-Assembly of Nanostructures” Edited by Stefano Bellucci, Springer (2012)
- “Semiconductor Material and Device Characterization”, D.K. Schroder, IEEE Press, A John Wiley & Sons, Inc (2006)
- “Transmission Electron Microscopy, a Textbook for Material Science”, D.B. Williams and C.B. Carter, Springer (2009)
- “X-Ray Metrology in Semiconductor Manufacturing”, D.K. Bowen and B.K. Tanner, Taylor & Francis Group (2006)
Electronic versions of all the above books are available through the University of Waterloo Library.
Marking scheme
- 50% Final Exams.
- 50 % Assignments.