Dear Saopeng,

you can measure stress/strain in the TEM by using dark field holography (Toulouse group at CEMES (France), Prof. Martin Hytch) or nanodiffraction mapping in STEM mode. The level of Strain you can measure is 10^-3 to 10^-4

Cheers

Bert

What do you mean with micro-stress?

Dear Shaopeng,

guessing you mean "materials" not samples, please could you provide how you define ?? vs. (as Duco also would like to know)

Possibilities:

microscopic stress [of the sample by e-beam],

micro-stress [grain structures, inherent properties of different compounds within a sample-grain boundaries, shear forces, etc. ), and

last but not least: which TEM sample do you have in mind: (resin embedded sample's) ultrathin sections, FIB-samples, etc.etc..

I am sure the more precise you ask, the mor precise the answer(s) will be.

Thank you in advance,

Wolfgang

Dear Saopeng,

you can measure stress/strain in the TEM by using dark field holography (Toulouse group at CEMES (France), Prof. Martin Hytch) or nanodiffraction mapping in STEM mode. The level of Strain you can measure is 10^-3 to 10^-4

Cheers

Bert

Thanks Bert for the clarification. Very interesting post.

only added for convenience: http://www.cemes.fr/:

Centre d’Elaboration de Matériaux et d’Etudes Structurales CEMES-CNRS (France)

+/- Introduction:

Development of methods for strain and stress measurement at the nanoscale: transmission electron microscopy

http://www.cemes.fr/index.php?option=com_flexicontent&view=items&cid=47%3Astress&id=312%3Anano-contraintes-tem&Itemid=192&lang=en

regards,

Wolfgang

Dear Shaopeng,

Of course, everything depends on what you call "micro-stress" ... but since the intensity in the diffraction spots are directely linked to the lattice organization, some strain will results to some variation of contrast in a TEM image. However they are many parameters affecting the contrast (thickness, materials, strain, ...), so extract the information of strain directly on a bright field TEM image is complex.

A nice work has been done by Prof. C. T. Koch on a technique called "Dark-field In-line holography" (DIH) where the strain is extracted using the variation of intensity on one darkfield image at different level of defocus. It can interest you since it is directly linked to your question "An efficient, simple, and precise way to map strain with nanometer resolution in semiconductor devices " ==> http://scitation.aip.org/content/aip/journal/apl/96/9/10.1063/1.3337090

There are other techniques to measure strain in a TEM at nanometer scale. Off axis Darkfield holography cited above is available for commercial use (software on HREM research website) and the reference paper by Prof. Hytch and al. is excellent "Nanoscale holographic interferometry for strain measurements in electronic devices" ==> http://www.nature.com/nature/journal/v453/n7198/abs/nature07049.html

I can advise a last paper made by Dr. Beche comparing different techniques able to measure strain in a TEM : "Strain measurement at the nanoscale: Comparison between convergent beam electron diffraction, nano-beam electron diffraction, high resolution imaging and dark field electron holography" ==>http://www.sciencedirect.com/science/article/pii/S0304399113000843

Regards,

Alex