Modeling Place

Matlab optimization

2007-03-06T15:53:00.000-06:00

Numerical issues are really severe for my current simulation with MATLAB. The computing speed is killing me if I use smaller time step for the purpose of stability, say, I have to wait for about 30 days to get sufficient results! That is not acceptable. So the past couple days, instead of switching to another language (this is also a time-consuming task), I spent lots of time to optimize my MATLAB code, and , fortunately, I did learn something and improved my code speed quite a lot. Now the speed is more than 10 times faster than before, which really surprised me. So I believe these experience are worthy of sharing:

Use sparse matrices when you can. They may save you a great deal of space and time. See matlab's sparse command.
Use matrix operations instead of for loops - i.e. vectorise your code.
Functions are faster than scripts - they get compiled internally the first time they are run.
If you know the maximum size that a matrix will be, create it that size initially, rather than letting it grow incrementally.
Use pack every so often to tidy up memory usage.

Much more than that, here is one great book writen by Peter Acklam:MATLAB array manipulation tips and tricks. This is something you can not get from regular commercial MATLAB books.

So if you have spent one week for writing your code, I strongly suggest you to spend one more week to optimize it . I bet you will get what you paid for.

Nature Materials: Wrinkles are good

2007-01-27T22:47:00.001-06:00

The current issue of Nature Materials highlights an interesting artcile using wrinkled thin films for fabricating microlens arrays. Check out the original paper by Chan and Crosby, Adv. Mater. doi:10.1002/adma.200601595 (2006). The wrinkling pattern looks quite interesting.

Buckling Analysis with ABAQUS

2006-12-23T12:16:00.000-06:00

In searching for helps with ABAQUS, I found this documentation page informational, although I am not sure if we are using Version 6.5.

The particular question I have at the moment is about a static buckling analysis. I found in Section 6.2 a good introduction to linear eigenvalue buckling predcition (6.2.3) and nonlinear post-buckling analysis (6.2.4).

The first step in buckling analysis is to find the critical load, which should be related to the lowest eigenvalue. However, to relate the output eigenvalues to the critical load, one must clarify the following:

(1) What is the base state? The buckling loads are calculated relative to the base state. This could be the initial condition or the current state of the model at the end of the last analysis step. Geometric nonlinearity may be included in the general analysis steps prior to the eigenvalue buckling analysis (a linear perturbation to the current state).

(2) Does the base state have a preload? It is not clear to me what this preload means and how it is specified in ABAQUS.

(3) What is the perturbation load pattern? This must be specified as applied load, which could be nodal forces, distributed pressure, or thermal load. The amplitude of the applied load is not important, becasue it will be scaled by the eigenvalues.

For example, to analyse buckling due to thermal stress, the critical temperature can be obtained by multiplying the lowest eigenvalue with the applied temperature, assuming a base state with zero preload.

ABAQUS Tutorial from Brown Univ.

2006-12-23T11:57:00.000-06:00

This link could be a good place to start learning ABAQUS.

Methods for the synthesis of nanoparticles and nanomaterials

2006-09-13T21:41:00.000-05:00

Synthesis of nanomaterials is what I am learning by taking Dr. Ferreira's course "Nanomaterials". Though it seems sort of way off the Mechanics projects we are doing, it does great help for better understanding of the materials properties at the Nano-scale level. I post a brief intruction about the methods for the synthesis of nanoparticles here, and hope you can get rough concepts about it.

iMechanica

2006-09-09T09:56:00.000-05:00

Dr. Zhigang Suo and his students at Harvard have set up a new multi-blog serving the research community in mechanics. Anyone can participate. See Why should you post in iMechanica and many other posts for details. My first post was on Modeling Place. We have been doing well here, but iMechanica offers much more. I urge you to register and post in iMechanica. Over time, we will migrate from Modeling Place to iMechanica, to be part of a larger community.

Nanodot: the original nanotechnology weblog

2006-09-07T18:25:00.000-05:00

Nanotechnology: from Feynman to Funding

2006-09-07T18:22:00.000-05:00

Nanotube resonators break gigahertz barrier

2006-09-07T17:59:00.000-05:00

Selected review article by Prof. Suo

2006-09-07T13:33:00.000-05:00

In Dr Suo's homepage, he posted his favorite review articles.

1. Micromechanics of macroelectronics
2. Reliability of interconnect structures
3. Motions of microscopic surfaces in materials
4. Mixed-mode cracking in layered materials

some of artilcles were mentioned by Dr Huang in his thin film mechanics class. These are really good articles.

Lecture Overheads on Delamination Mechanics

2006-08-28T16:09:00.000-05:00

Prof. Hutchinson open his unpublished lecture note. you can look at his homepage. I linked his lecture notes. If you are interested in this subject, it will be useful.

Nanomechanics: Response of a Strained Semiconductor Structure

2006-08-22T14:15:00.000-05:00

This nature paper, given by F. Liu, M.G. Lagally et. al, raised a very interesting issue about the thin template layer curvature induced by growing self-assembled Ge quantum structures.

Dr. Huang, I think some potential issues are there for us to work on in future, since we group already did something with respect to viscous substrate wrinkling problem and self-assembly growing of Ge on Si. Combination of part of the two mechanisms may be helpful.

Nanoscale patterning with block copolymers

2006-08-21T17:32:00.000-05:00

Recent Materials Today cover story: The self assembly of block copolymers offers new strategies to create patterns on the nanoscale. The polymeric constituents, substrate surface properties, and experimental conditions allow the control and optimization of patterns for specific applications. The method offers interesting possibilities in combination with high-resolution lithography methods, and could become of particular in microtechnology and biosensing ... Click here to read the full story.

Deformation in nanocrystalline metals

2006-08-20T22:04:00.000-05:00

The paper below gives a good reviews on the deformation behavior and mechanisms in nanocrystalline metals by atomistic simulations.

http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X1J-4JS1N7J-W-Y&_cdi=7244&_user=10&_orig=browse&_coverDate=05%2F31%2F2006&_sk=999909994&view=c&wchp=dGLzVzz-zSkzV&md5=074971b1ba8ccb485b769e690d4241be&ie=/sdarticle.pdf

Summer School on Cell and Molecular Mechanics

2006-08-19T23:41:00.000-05:00

AMN: GEM4 Summer School "Cell and Molecular Mechanics in BioMedicine"

Sandia experimental package of piezoelectric films to be part of NASA space station experiment

2006-08-15T13:29:00.000-05:00

This news is about piezoelectric polymer films which are developed by Sandia people. These films can be used as ultra-lighr mirrors in space telescopes. If films are made of polymer, what happen at high and low temperature in space?

A BRIEF HISTORY OF GRC

2006-08-07T14:39:00.000-05:00

I got a pretty good impression on this conference. we attended excellent seminar and poster session. Most of all, I can meet good people and talk each other. If possible, I will attend next gordon conference. I hope you guys meet there.

Moore's law:the future of Si microelectronics

2006-08-06T00:34:00.000-05:00

This is the newest review about the future of Si microelectronics, key issues at the end of the Si roadmap, and the time frame for possible non-Si technology replacements. As the researchers in thin film areas, I think we should be aware of the directions where the industry will be, and that may help us to explore possible mechanics issues in future.

Thermal stress evolution in embedded Cu/low-k dielectric composite features

2006-07-30T23:06:00.000-05:00

With the scaling down in integration circuitry, device reliability attracts more and more attention of researchers. Among the key factors that influence the reliability, thermal stress distribution depends on both material properties and geometry of such systems.

http://scitation.aip.org.content.lib.utexas.edu:2048/getpdf/servlet/GetPDFServlet?filetype=pdf&id=APPLAB000089000001011913000001&idtype=cvips

Material challenge for flexible organic devices

2006-07-24T00:11:00.000-05:00

This article highlighted two major technical challenges that are common to most flexible electronic technologies. Apparently, both of them are relevant with mechanics issues.

Towards frictionless nanomachines

2006-07-21T15:58:00.000-05:00

Friction is a big problem in nanosized devices because they have huge surface-to-volume ratios, which means that their surfaces quickly wear out and seize up. Traditional lubricants are useless in such machines ... Two independent groups of researchers have taken improtant steps in overcoming friction in nanosized mechanical devices ... Highlighted by physicsweb, IOP.

Materials science: Carbon sheet solutions

2006-07-21T13:12:00.000-05:00

(Nature 442, 254-255)

The graphene sheets can be used instead of carbon fires and nanotube. But these have a poor mechanical properties. This problem could be solved by making a composite material of graphene sheets and polymers although it is difficult to make. One of solutions is proposed by Stankovich et al (Nature 442, 282-286).

NANOTECHNOLOGY: Pretty as You Please, Curling Films Turn Themselves Into Nanodevices

2006-07-14T14:25:00.000-05:00

One of difficulties in nanotechnology is how to make the structure which you want to. Roughly speaking, most of nano structure is 2D, but if you can control the shape, there are a plent of application.

Soft matter with hard skin

2006-07-13T17:34:00.000-05:00

A review ariticle on wrinkling by Jan Genzer and Jan Groenewold. The authors start with a general discussion of human skin wrinkles, which is probably the most common and the most important wrinkles. The simple mechanics of buckling is reviewed, togethter with recent experiments on elastic and viscoelastic foundations as well as some applications. A total of 87 references are cited, some of which look very interesting for further studies of wrinkling phenomena.

Applied Mechanics News: Cellular and Molecular Mechanics

2006-07-12T22:29:00.000-05:00

by Philip LeDuc, Department of Mechanical Engineering, Carnegie Mellon University.

Testing System Analyzes Materials at the Micro to Nano Level

2006-07-10T02:38:00.000-05:00

It is known universally that material often behaves differently in the micro- or nano scale than in the macroscopic world. New testing methods are demanded consequently. This is a brief introduction for one new testing method: NanoDAC. I think it is interesting and will keep tracking in it to get more details.

http://www.nanotechbriefs.com/blog/tech_10_1205.html

Adding defects to CNT walls

2006-07-09T19:07:00.000-05:00

Here is a report on a new method to add defects to carbon nanotube walls that was developed by researchers at the U.S. Department of Energy's Argonne National Laboratory.
http://www.anl.gov/Media_Center/News/2006/MSD060630.pdf
The team found the method of adding defects to nanotubes by computer simulation tools.
This could be an improvement for the strong nanotube structure.

Thin Film Wrinkling in Metrology

2006-07-07T10:18:00.000-05:00

Measuring the Modulus of Soft Polymer Networks via a Buckling-Based Metrology (Wilder et al., Macromolecules 39, 10.1021/ma060266b, 2006).

Highlighted in Science Magazine: Buckle Up for Softy

NIST News: Soft Materials Buckle Up for Measurement

A group of NIST Scientisits apply wrinkling pheonomenon to measure mechanical properties of soft materials, based on the mechanics of thin film buckling. They have also applied this method to ultrathin polymer films (less than 30 nm thick), in which case the mechanics is slightly modified to take into account the surface effects. Dr. Huang collaborated with this group on another paper, Elastic Moduli of Ultrathin Amorphous Polymer Films (Macromolecules 39, 10.1021/ma060790i, 2006). Many interesting mechanics questions remain open for the wrinkling phenomenon, and its potential applications (including nanometrology) are yet to be explored. A harmonic collaboration between experimentalists and theoreticians (mechanicians, in particular) is essential.

Does temperature exist at the nanoscale?

2006-06-26T17:56:00.000-05:00

Surprisingly, whether temperature exists at small scales depends on what temperature you're talking about, a PRL paper showed (Highlighted by APS Physics Tip Sheet #44). It's a problem of definition. Are things meaningfully defined on nanometer length scales? We need to think about it. Generally speaking, all things defined in macroscopic, continuum or statistical theories need to be examined when it comes to small scales. And measurements are also concerned.
Physicists questioned about temperature. How about stress? Modulus? What are the stresses in, for example, carbon nanotubes and DNAs? Can we, and do we have proper ways to measure them in experiments? How to define the contact area in low dimensional(1-D, 2-D) systems? What do you think?

Microchip pushed to record operating speeds

2006-06-20T15:23:00.000-05:00

This would be awesome if can be turned into commercial products:
http://www.newscientisttech.com/article/dn9368-microchip-pushed-to-record-operating-speeds.html

Inorganic Electronics Begin to Flex Their Muscle

2006-06-19T14:44:00.000-05:00

http://www.sciencemag.org/cgi/reprint/312/5780/1593.pdf

In near future, mechanical engineer will do this kind of analysis in a mechanics point of view.

Researchers Reveal New Insights into the Surface of Silicon Semiconductors

2006-06-19T01:09:00.000-05:00

http://www.physorg.com/news69693841.html

MEMS applications using diamond thin films

2006-06-17T22:25:00.000-05:00

Interesting!
http://sst.pennnet.com/Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=253400&VERSION_NUM=2&p=5

NIST Bullet Tests Make Frangibles More Tangible

2006-06-14T22:03:00.000-05:00

http://www.nist.gov/public_affairs/techbeat/tb2006_0608.htm#bullet

This link is not related to our research. you can watch pretty interesting movies files (clip1 and clip2). Can we consider it as dynamics fracture?

DNA and carbon nanotube micromachines

2006-06-13T12:52:00.000-05:00

One of recent APS Physics Tips Sheets put two interesting PRL papers together: one reports that DNAs turn rotation into translation, and the other tells carbon nanotubes turn translation into rotation. Click here and scroll down to see the tip.

What is a Quartz Crystal Microbalance - QCM?

2006-06-10T01:48:00.000-05:00

This article is about history and basic principles of QCM. QCM is a widely used sensor for measuring small mass and liquid phase properties etc.(Detailed applications are listed in the article.) This article helped me a lot in preparing my presentation in IEEE FCS.

http://www.pharmaceutical-int.com/categories/qcm-technology/what-is-a-quartz-crystal-microbalance-qcm.asp

Nanotechnology's Big Question: Safety

2006-06-09T13:47:00.000-05:00

Very little is known about the safety risks presented by engineered nanomaterials. But it becomes a more and more important problem for researchers to explore right now:

http://www.washingtonpost.com/wp-dyn/content/article/2005/10/22/AR2005102200995.html

Introduction of Flip Chip

2006-06-09T09:00:00.000-05:00

Flip chip package is the state of the art technology of microelectronics field due to electrical performance. But the increase of device density on the chip cause mechanical problem which I try to understand and solve. What is flip chip? This web site gives us brief introduction and tutorials. Click here for the introduction of flip chip. If you want to know more information, you can also see full toturials and photos etc.

Plastic Deformation of Freestanding Thin Films

2006-06-03T17:32:00.000-05:00

Plastic response of crystalline solids exhibit a strong size dependence on micro- and nano-scales. This is a good article on the experiments and modeling aspects for this issue:

http://www.deas.harvard.edu/vlassak_group/publications/42_fs27.pdf

Growing Glowing Nanowires to Light Up the Nanoworld-by NIST

2006-06-02T09:16:00.000-05:00

This article is about one of applications of nanowire. Although the content is short, the photo is very interesting. Click here for short article.

Atomic force microscope sorts molecules out

2006-05-15T22:54:00.000-05:00

An interesting usage of AFM:
http://nanotechweb.org/articles/news/5/5/1/1

Wikipedia and Applied Mechanics

2006-05-08T02:05:00.000-05:00

AMN: Wikipedia and Applied Mechanics

My first contribution was a new entry for R.D. Mindlin, one of the Timoshenko Medal recipients.

Impact of Mechanics on Reliability of Interconnect Structures in Microelectronics

2006-05-01T09:48:00.000-05:00

Professor Paul S. Ho recently gave a seminar at the Center for Mechanics of Solids, Structures and Materials, delineating the impact of mechanics research on the development of future interconnect technology in microelectronics. Click for his abstract and slides.

50-year-old magnetic mystery solved - quantum structure obeys classical physics

2006-05-01T00:41:00.000-05:00

An interesting report.
http://www.brightsurf.com/news/jan_04/EDU_news_010704.php

Reliability Challenges in Roadmap

2006-04-27T09:12:00.000-05:00

News from Integrated Structures Committee: Reliability Challenges in Roadmap: Opportunities for Mechanics

How to calculate hardness

2006-04-24T12:40:00.000-05:00

An interesting article:
http://physicsweb.org/articles/news/10/3/7/1

More details are given by reference: Phys. Rev. Lett. 96, 085501 (2006)

Vision of the Future of Solid Mechanics - by Zdenek Bazant

2006-04-21T11:32:00.000-05:00

Click here for the ariticle as Guest Editorial in Journal of Applied Mechanics, March 2006.

Solid Mechanics and Quantum Mechanics

2006-04-15T15:17:00.000-05:00

AMN: Ramblings on Solid Mechanics-Quantum Mechanics Link

An interesting read, to begin thinking about quantum mechanics.

Introduction of Thin Film Deposition Process

2006-04-13T21:16:00.000-05:00

Considering that our researches are relative to thin films, I think it is somewhat necessary to know briefly about the deposition process of thin films. The following link leads to a short but clear introduction.

http://www.answers.com/topic/thin-film-deposition

New Directions in Mechanics

2006-04-12T13:22:00.000-05:00

One year old article, but still a quite good review of the cutting-edge research directions for the Engineering mechanics.

http://www.nano.me.berkeley.edu/docs/Kassner_etal_MoM'05.pdf

Screen Capture Program

2006-04-09T23:20:00.000-05:00

How do you make figures on your screen? In my case, I usually use screen capture program. If I use "copy figure" option in MATLAB directly, sometimes it makes word file bigger and slower. This program is useful for that case. you can save as general figure file like jpg, gif, bmp or use "copy and paste" easily. But if you want to make high resolution ps file, you just follow steps which posted by Dr Huang.
you can download this program at http://www.faststone.org/

Basic Usage:
(1) Download and install the software
(2) Click "setting"
(3) Define "hotkey"
(4) In my case, I define capture rectangle region as "PrtSc"
(5) If you click "Print screen" key on your keyboard, crosshair shows up.
(6) After select corner of rectangle, you can save figure using "right mouse button" or copy figure as "Ctrl+C".

Writing and Reviewing, by Bob Rapp

2006-04-05T15:10:00.000-05:00

Click here for a short article on writing and reviewing.

Self-Assembling Nano-Electronics Turn a Corner

2006-04-04T00:26:00.000-05:00

http://www.nsf.gov/news/news_summ.jsp?cntn_id=104217

Modeling the stuff of the material world

2006-03-30T19:38:00.000-06:00

Here's an "old" but good article written by Prof. Rob Phillips of Caltech: Modeling the Stuff of the Material World: Do We Need All of the Atoms? Prof. Phillips was a mechanician at Brown and now is a mechanician and applied physicist at Caltech, with research interests shifted from solid mechanics to mechanics and physics of biological systems. On his group homepage, you may have much fun.

Flexible Electronics

2006-03-30T13:41:00.000-06:00

AMR: Review articles on Flexible Electronics

Understanding Nanotubes : properties, applications, production, markets and utility

2006-03-30T00:16:00.000-06:00

What exactly the nanotube is and why a great many people are diving into the game of playing the "tubes"? The following link leads to a practical guide to understanding their properties, applications, production, markets and utility.

http://www.nanovip.com/forums/showthread.php?t=1059

Produce high-resolution figures for publications

2006-03-25T13:31:00.000-06:00

Yesterday I spent more than 2 hours trying to generate high-resolution figure files for a paper accepted by Journal of Materials Research. While many other journals are less strict on resolution, I had a similar experience with Thin Solid Films and IEEE Transactions. Also, from authors' point of view, we should always provide figures with best quality in our publications. As a research group, we should try to develop a consistent approach to producing high-quality figures of scholarly style. To do this, we should share successful stories so as to save the effort collectively. I will start here with my story.

Group members and other friends: please follow up by adding comments to this post. Once we have a good collection, we will make a standard, at least for our group.

In this particular paper, I have seven figures, including some generated by Matlab, some by my co-authors using Sigmaplot (I don't have the software, and the co-author is not available to help), and some sketches generated in MS Word. The journal specifically requires a resolution of 1200 dpi and 3 inch width. Only tif or eps files are acceptable. I can make tif files using Adobe Photoshop, but the resolution is only 72 pixels per inch. Changing it to 1200 pixels per inch makes each figure file more that 30 Mb, too big to be sent out by email. Even this, the print-out of the figure does not look much better. On the other hand, the figures in the pdf file generated from the word file look very good. At this point, I realized that the pdf file is generated by printing to a file with Adobe Acrobat Distiller, where the resolution is controlled by the "printer" rather than the word file or the figures embedded in it. Suddenly, I remembered that, from my earlier experience in Princeton where I used LaTex and embedded figures in ps/eps format, many printers work as postscript (ps) output device. One can simply print the original file to a target ps file by choosing a PS printer and selecting desired resolution there. Fortunately, I do have a PS printer connected to my computer, and it worked out very nicely: high-resolution figures in small-size ps files (< 1Mb). Now let me summarize what I did:

(1) Start from the word file with all figures (it does not matter how the figures were generated).

(2) For each figure, copy to a new word file (say, Fig1.doc).

(3) Print Fig1.doc: choose a PS printer, select the desired resolution in "Properties", and check the box for "Print to file".

(4) Name the target print file as "Fig1.ps" or "Fig1.eps". An error would occur if the selected printer is not PS type.

(5) After printing, open the ps/eps file with GSview (free download from ghostscript).

Nano or Bio

2006-03-23T09:15:00.000-06:00

AMN: Whither nano or bio (by Rob Ritchie).

Im wins CNM award

2006-03-22T15:52:00.000-06:00

Congratulations to Se Hyuk Im, who wins the Seminar Attendance Award from the Center for Nano- & Molecular (CNM) Science and Technology and the Doctoral Portfolio Program in Nanotechnology of the University of Texas at Austin. Se Hyuk is recognized for having attended all CNM seminars for the last one and a half years. A certificate and a check of $50 were presented to Se Hyuk on March 22 at the lunch party of the Portfolio Program.

Good job!

News Release: Huang Receives NSF CAREER award

2006-03-16T15:20:00.000-06:00

A news release from College of Engineering, University of Texas at Austin.

Thanks to all group members for works that led to this award.

How to Write a Paper

2006-03-05T21:48:00.000-06:00

AMR: Professor Mike Ashby's booklet on "How to Write a Paper"

SBES: Simulation-Based Engineering Science

2006-03-03T15:59:00.000-06:00

Applied Mechanics Research and Researchers: SBES: Simulation-Based Engineering Science

Technology Inspiration: SOI and Strained SOI

2006-02-11T11:53:00.000-06:00

From Advanced Substrate News, No. 2, Summer 2005

Editorial, by Dr. Andre-Jacques Auberton-Herve, Chairman and CEO of The Soitec Group

Ten years ago, we were a handful of believers; now, SOI is an integral part of device optimization on the leading edge. Nowhere is this more apparent than in the high-performance microprocessor market. Advanced substrates, led by SOI, address the challenges of heat dissipation, power consumption, process integration and performance.

IBM’s SOI Power

“Like our copper chips, SOI will accelerate the industry’s constant drive to create smaller, more powerful, less expensive electronic goods.” (Mike Attardo, General Manager, IBM Microelectronics)

“Our decades-long commitment to pursuing and rapidly implementing technology breakthroughs like SOI and strained silicon is paving the way for a new generation of power savvy chips.” (Bernard S. Meyerson, IBM Fellow and chief technologist)

The 64-bit PowerPC 970FX announced just last year (2004), was the first in the industry to combine SOI, strained silicon and copper technologies in 90nm, 300mm production, no less.

AMD’s Momentum Building

AMD claims the title of being the first company to bring SOI to microprocessor production.

As AMD momentum grows in the enterprise and companies scramble to catch up, the company is extending its performance lead even further with the introduction of new multi-core AMD64 processor designs. These 90nm products also benefit strongly from AMD’s second generation of localized strain engineering, co-developed with IBM. The technology, which is commonly referred to as “dual stress liner” or DSL, works in concert with SOI to deliver a 24% boost in transistor speed with no increase in power.

Freescale’s Embedded High Performance

As of this year (2005), the company is shipping four new next-generation PowerQUICC III processors based on 90nm SOI and copper. Freescale says this enables the processors to deliver high performance with low power dissipation, bringing gigahertz-class performance to the enterprise networking, telecom transmission and switching, 3G wireless infrastructure, storage and high-end imaging markets.

SOI and sSOI Address MPU Clock Speed Challenge (by Jean-Marc Lemeil, Soitec)

IC makers need both local and global strained SOI to win the GHz race.
Strain and SOI lead to Faster, Cooler Transistors (by Randhir Thakur, Applied Materials, Inc.)

Key among the advanced technologies that contribute to faster transistor speeds with reduced leakage are strained silicon and silicon-on-insulator (SOI).

Professor’s Perspective (by Sorin Cristoloveanu, ENSERG, France)

The most fascinating application of Smart Cut is the material transformation: from SOI (silicon on SiO2) to SOI (semiconductor on insulator), Replacing the conventional silicon film by strained Si, SiGe, Ge, GaN, SiC, and so forth, opens revolutionary applications in microelectronics, nanoelectronics and optoelectronics. Additionally, the buried oxide can be substituted by a whole range of dielectrics. Quartz, glass and diamond are envisioned for transparent devices and MEMS. Buried alumina or aluminum nitride is expected to solve the problem of power dissipation in ultra-dense VLSI chips. We won’t need another decade to find these innovative Smart Cut enabled materials in the catalogue.

R&D Outlook (by Carlos Mazure, Soitec)

The high performance path will drive the most advanced substrates and material innovations. Engineered substrate solutions include ultra-thin (UT) SOI, mobility enhancing substrates like strained SOI (sSOI) in addition to local strain techniques, as well as improved thermal dissipation to reduce the impact of hot spot impact.

Min's Paper on Trapped Vibrations

2006-02-01T00:27:00.000-06:00

Published in the February issue of IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, this paper first reviews torsional vibrations in circular plates and then shows that the first-order torsional modes can be trapped within a circular stepped region. The theoretical finding was supported by experiments in a previous publication. Potential applications include torsional-mode resonators with ultrahigh quality factors for sensing applications, with a clear advantage over the conventional thickness-shear-mode resonators when working in contact with liquids. In collaboration with Texzec, Inc., we are exploring various structures (e.g., convex plates) and materials (e.g., polymers) and investigating the effect of liquids, both theoretically and experimentally.

On Thin Film Wrinkling

2006-01-30T21:12:00.000-06:00

Our group has been studying wrinkling for several years. Here is a brief outline of previous works:

wrinkling on elastically compliant substrates
wrinkling on viscous (linear creep) substrates
ratcheting-induced wrinkling on metal (plastic) substrates
wrinkling on viscoelastic (polymer) substrates
electricially induced wrinkling of thin film electrodes

Recently, our focus is on the dynamics of wrinkle evolution (including growth and coarsening) and on the transition among various wrinkle patterns.

Try a new way of research

2006-01-30T21:06:00.000-06:00

Let's try to use Blog to share research experience and ideas among the members of our research group and our friends.