1.2 Exercises and Seminar

1.2.1 Topics for Seminar

Which group will deal with which topic will be decided in the first week of the class.
You may choose your subject from the list, or suggest a subject of your interest which is not on the list.
Presentation will be at the second half of the term (or, if so demanded, in the semester break); the beginning date depends on the number of participants
You will get some materials to start you and help from teaching assistents

List of Topics

Thermodynamics of Point Defects in Ionic Crystals
Explain the different formal concepts of looking at point defects with the "metallurgist" approach and the "chemical potential" approach
Deal with a few examples in both approaches
Expand the chemical potential approach to some specific examples as e.g. an oxygen sensors.
Point Defect complexes in Silicon Crystals
Start from point defects in thermal equilibrium; consider their agglomeration during cooling
Historical/Experimental: The A-,B-,C,-, D-defects, the interstitial controversy
Present view; simulation and role of oxygen/carbon
Point Defects and Diffusion in Silicon
20.12.99.
The self-diffusion problem; role of interstitials; unknown parameters
Diffusion of dopants and other substitutional impurities
Interstitialcy mechanism and significance
State of the art: Complete simulation of all point defect reactions.
Dislocations and Plastic Deformation in Hexagonal Crystals
10.1.2000
Describe the specialities of plastic deformation in hex. crystals as a function of the crystal and defect symmetry
Give examples, discuss the technical importance.
Dislocations and Plastic Deformation in bcc Crystals
Describe the specialities of plastic deformation in bcc crystals. Consider glide systems, the role of screw dislocations
Cinsider low temperatur deformation; twinning as a deformation mode
Memory Shape Alloys
17.1.2000
History, basic structures and mechanisms
Reversibel deformation - defects and defect mechansims involved
Applications, state of the art, outlook
Defects in Quasicrystals
24.1.2000
History, general background for periodic tilings in 2 Dimensions
Quasicrystal sas projections from 6-dim. crystals
Point defects and diffusion
Phasons and quasi-dislocations
State of the art and problems
X-Ray Methods for Investigating Defects
General considerations
Loking at Bragg peaks and in between Bragg peaks
Defect imaging with x-rays (Berg-Barrett, x-ray topography); Advantages and limitations
Oxidation Induced Stacking Faults in Si (OSF)
General aspects; historical development
Role of metal impurities for nucleation
growth kinetics, present status and state of the art in avoidance of OSFs
Epitaxial Silicides
31.1.2000
Overview of epitaxial Silicides
Special role of Ni- and Co-Silicides
Kinetics and phase diagrams
Interface structure
Compliant Substrates
7.2.2000
Problem of misfit, basic concept of compliant substrates
Techniques of waferbonding, special conditions for compliant substrates
State of the art, possibilities and problems
Models for interface reactions and dislocation reshuffling


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