Wu's cemm 430 Web

Objectives--A Revision Necessitated by Miniaturization:

CME 430 and 530 (THEORY OF ELASTICITY I & II) are still being revised to broaden their traditional concentration on only mechanical cause and effect to include incompatible deformations brought about by the movements of atoms in solids. The nonuniform elastic fields accompanying such incompatible deformations can, in turn, provide additional driving forces for continued diffusion. With this additional consideration in mind but still retaining the emphasis on elasticity, I have chosen a new title for the revised sequence: DIFFUSIOELASTICITY.

Elasticity has been one of the workhorses of today's technological world since the beginning of the Industrial Revolution. The industrial needs of the period have made mechanical load a primary concern of most of the developments. Focusing on mechanical cause and effect alone, elasticity has gradually evolved into a sophisticated mathematical theory that is also amendable to powerful numerical algorithms that are capable of solving practically all realistic problems, as long as the dimensions in question are not too small. Actually, there are indications that the mechanical aspects of elasticity remain valid even when the dimensions are diminished to the submicron world--say, a few hundred nano-meters. However, the drastically increased surface-to-volume ratio requires the addressing of surface effects (surface tension, surface stress and stiction, to name a few) and the mechanical effect due to the transport of atoms (deformations caused by 'electron wind'-displaced ions in a thin metallic interconnect, for example). None of these is considered in a traditional elasticity course, but many of them may be integrated into elasticity via the introduction of an eigenstrain without too much additional effort. The outcome of such a modified theory is a combined effect of thermo-, electro- and elasto-transport which is pretty much what one needs to know about a MEMS, if not quite an NEMS.

The need to consider small material structures is, of course, driven by the so-called Silicon Revolution. The transistor invented in 1947, the integrated circuit developed twelve years later, and the drive to pack more and smaller transistors on a single piece of silicon have been fueling the miniaturization process in the microelectronic industry for the past half a century. The process has moved from small-scale integration (SSI) to very-large-scale integration (VLSI) and is now in a stage of continued shrinking of device dimensions in ultra-large-scale integration (ULSI). The task of exploring new device structures that are based on quantum mechanical effects has turned into one of the last resorts of the industry and, in fact, become more urgent. These devices have critical dimensions smaller than the quantum mechanical wavelength of electrons. One such group of devices is based on self-organized arrays of semiconductor islands of several hundred to several thousand angstroms in size that are formed during hetero-epitaxial growths. These islands are referred to as self-assembled quantum dots--quantum wires in 2-dimension. They are difficult to manufacture using standard lithographic techniques, but the self-assembly phenomenon, which has not been fully understood, may be exploited to produce quantum dots of uniform size and spatial distribution. Incompatible deformations are major energy sources in most electronic systems. They create undesirable reliability problems, but can also be exploited to enhance self-assembly. There is definitely a need for elasticity to move from the world of large structures to the materials space of reduced dimensions.

Topics(To be chosen from the following list):

Elasticity

Strain
Stress
Equations of elasticity
Two-dimensional elastostatics

Eigenstrain

Equations of elasticity with eigenstrain
Two-dimensional problems
Temperature related eigenstrain
Vacancy related eigenstrain
Composition related eigenstrain

Thermodynamics of continuous media
Thermoelasticity
Diffusioelasticity
Diffusion and Transport phenomena in solids

Thermo-transport
Electron wind and electromigration
Elasto-chemical potential and elasto-transport

Introduction to advanced topics for CEMM 530

Surface energy and surface phenomena
Surface diffusion
Stability and evolution of epifilms on substrates
Stability and evolution of alloy epifilms on substrates
Motion and evolution of voids

Text:Introduction to the mechanics of a continuous medium. Malvern, L. E., Prentice Hall, 1969.

Reference:

Mathematical theory of elasticity. Sokolnikoff, I. S., McGraw-Hill, 1946.
Theory of elasticity. Timoshenko, S., McGraw-Hill, 1970.
Mechanics of continua. Eringen, A. C., R. E. Krieger Pub. Co., 1980.
The mechanical properties of matter. Cottrell, A. H., John Wiley & Sons, Inc., 1964.
Diffusion in solids. Shewmon, P., The Minerals, Metals & Materials Society, 1989.

Academic honesty:
You are encouraged to work on the assignment problems with your fellow students. However, the assignment solution that you turn in for credit should reflect your own understanding learned from the group discussion. Do not copy directly from work of other students. Academic dishonesty is a severe breach to the student's code.


Your Instructor:
					Dr. Chien H. Wu Professor of Mechanics and Materials Department of Civil and Materials Engineering University of Illinois at Chicago 842 West Taylor Street Chicago, Illinois 60607-7023 Office: 3079 ERF Phone: 312-413-2644 Fax: 312-996-2426 E-mail: cwu@uic.edu
Objectives--A Revision Necessitated by Miniaturization: CME 430 and 530 (THEORY OF ELASTICITY I & II) are still being revised to broaden their traditional concentration on only mechanical cause and effect to include incompatible deformations brought about by the movements of atoms in solids. The nonuniform elastic fields accompanying such incompatible deformations can, in turn, provide additional driving forces for continued diffusion. With this additional consideration in mind but still retaining the emphasis on elasticity, I have chosen a new title for the revised sequence: DIFFUSIOELASTICITY. Elasticity has been one of the workhorses of today's technological world since the beginning of the Industrial Revolution. The industrial needs of the period have made mechanical load a primary concern of most of the developments. Focusing on mechanical cause and effect alone, elasticity has gradually evolved into a sophisticated mathematical theory that is also amendable to powerful numerical algorithms that are capable of solving practically all realistic problems, as long as the dimensions in question are not too small. Actually, there are indications that the mechanical aspects of elasticity remain valid even when the dimensions are diminished to the submicron world--say, a few hundred nano-meters. However, the drastically increased surface-to-volume ratio requires the addressing of surface effects (surface tension, surface stress and stiction, to name a few) and the mechanical effect due to the transport of atoms (deformations caused by 'electron wind'-displaced ions in a thin metallic interconnect, for example). None of these is considered in a traditional elasticity course, but many of them may be integrated into elasticity via the introduction of an eigenstrain without too much additional effort. The outcome of such a modified theory is a combined effect of thermo-, electro- and elasto-transport which is pretty much what one needs to know about a MEMS, if not quite an NEMS. The need to consider small material structures is, of course, driven by the so-called Silicon Revolution. The transistor invented in 1947, the integrated circuit developed twelve years later, and the drive to pack more and smaller transistors on a single piece of silicon have been fueling the miniaturization process in the microelectronic industry for the past half a century. The process has moved from small-scale integration (SSI) to very-large-scale integration (VLSI) and is now in a stage of continued shrinking of device dimensions in ultra-large-scale integration (ULSI). The task of exploring new device structures that are based on quantum mechanical effects has turned into one of the last resorts of the industry and, in fact, become more urgent. These devices have critical dimensions smaller than the quantum mechanical wavelength of electrons. One such group of devices is based on self-organized arrays of semiconductor islands of several hundred to several thousand angstroms in size that are formed during hetero-epitaxial growths. These islands are referred to as self-assembled quantum dots--quantum wires in 2-dimension. They are difficult to manufacture using standard lithographic techniques, but the self-assembly phenomenon, which has not been fully understood, may be exploited to produce quantum dots of uniform size and spatial distribution. Incompatible deformations are major energy sources in most electronic systems. They create undesirable reliability problems, but can also be exploited to enhance self-assembly. There is definitely a need for elasticity to move from the world of large structures to the materials space of reduced dimensions. Topics(To be chosen from the following list): Elasticity Strain Stress Equations of elasticity Two-dimensional elastostatics Eigenstrain Equations of elasticity with eigenstrain Two-dimensional problems Temperature related eigenstrain Vacancy related eigenstrain Composition related eigenstrain Thermodynamics of continuous media Thermoelasticity Diffusioelasticity Diffusion and Transport phenomena in solids Thermo-transport Electron wind and electromigration Elasto-chemical potential and elasto-transport Introduction to advanced topics for CEMM 530 Surface energy and surface phenomena Surface diffusion Stability and evolution of epifilms on substrates Stability and evolution of alloy epifilms on substrates Motion and evolution of voids Text:Introduction to the mechanics of a continuous medium. Malvern, L. E., Prentice Hall, 1969. Reference: Mathematical theory of elasticity. Sokolnikoff, I. S., McGraw-Hill, 1946. Theory of elasticity. Timoshenko, S., McGraw-Hill, 1970. Mechanics of continua. Eringen, A. C., R. E. Krieger Pub. Co., 1980. The mechanical properties of matter. Cottrell, A. H., John Wiley & Sons, Inc., 1964. Diffusion in solids. Shewmon, P., The Minerals, Metals & Materials Society, 1989. Academic honesty: You are encouraged to work on the assignment problems with your fellow students. However, the assignment solution that you turn in for credit should reflect your own understanding learned from the group discussion. Do not copy directly from work of other students. Academic dishonesty is a severe breach to the student's code. For current-semester class materials and announcements, [ enter ] [ blackboard ]
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