Electron microscopy
Sungwoo Sohn, PhD
About the instruments
TEM
While the software and electron optics share a great deal with the 200kV TEMs found in the Yale Medical School, the FEI Tecnai Osiris 200kV TEM is equipped with a new type of high-brightness electron source and a new high-area solid-angle x-ray detector, making possible high-speed spectral imaging. This new generation of electron microscope is operated from a remote console, making use of motorized apertures and high-resolution video cameras to keep human operators removed from the sensitive electron optics.
SEM
Two Hitachi SU-70 scanning electron microscopes provide 1 nm resolution with a high-brightness electron source. Both SEM instruments accelerate electrons from 0.5 to 30 kV, and are equipped with an energy filtered BSE detector above the objective lens. One of the microscopes (“R2D2”) has an energy dispersive x-ray detector for elemental analysis, while the other (“C3PO”) is equipped with a solid-state backscatter detector for enhanced imaging of grain boundaries. Dual objective magnets allow the user to switch between field-immersion and non-field modes.
Available to Yale researchers & external researchers
Specifications
| Point resolution | 0.25 nm |
| Information limit | 0.14 nm |
| Spherical aber. coef. | 1.2 mm |
| Chromatic aber. coef. | 1.1 mm |
| Maximum tilt | ±30 |
| Brightness @200kV | 1.8e9 A/cm²srad |
| EDX resolution | 136 eV |
| Accel. voltage | 0 to 30 kV |
| Resolution @30kV | 1 nm |
| Max sample size | 10cm dia. x 1cm high |
Rates
Rates in US$/hour unless otherwise noted
| Yale academic | External academic | Industrial | |
|---|---|---|---|
| SEM, Hitachi | 37 | 61 | 215 |
| AFM, Bruker | 35 | 58 | 105 |
| e-beam, EBPG | 100 | 165 | 300 |
| TEM, FEI Osiris | 100 | 165 | 300 |
| Ion mill, Fischione | 37 | 61 | 111 |
| Ion mill, Hitachi | 37 | 61 | 111 |
| Gold sputtering | 20 | 32 | 76 |
| Iridium sputtering | 20 | 32 | 76 |
| Microtome, Leica | 30 | 50 | 90 |
| HSQ resist, 4 ml | 25 ea | 41 ea | 75 ea |
| CSAR resist, 4 ml | 20 ea | 33 ea | 60 ea |
| Dektak profilometer | 10 | 16 | 45 |
Training & services
We have recorded a set of video clips for TEM and SEM training. You will be at the TEM or SEM, watching and copying the videos, while the instuctor is nearby and available for questions. You will stop the videos at various times so that the instructor can check your progress. This seems to work pretty well, and people like going through the course at their own pace. You might take one hour, or you might take four hours. It’s up to you. Sign up for training by using this appointment calendar.
The hard part of TEM training is showing you how to use the load lock. But we found a way! The Gibbs shop made us a “load lock simulator” that lets you practice without abusing the vacuum pumps. Neat!
Contact
Cheat sheets
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tem_cheat_sheet_v6.pdf (669.38 KB)TEM cheat sheet
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flat_polishing.pdf (653.29 KB)Flat polishing
Prep tools
TEM
In support of TEM sample preparation, the YINQE laboratory is also equipped with a Fischione 1050 ion-beam thinning tool, a focused ion-beam instrument, and a cryo-microtome.
Microtome
A microtome makes possible the sectioning of soft material for TEM analysis. Accessories for the Leica Ultra UC7 include a trimming mill and a glass knife maker.
Materials suitable for microtome slicing include polymer beads, carbon nanotubes, electro-spun fibers, and soft metals. YINQE supports only room-temperature operation.
More expertise in low-temperature sectioning and staining can be found at the Yale Medical School TEM facility.
SEM
Cressington 208 iridium sputtering tool
Iridium is useful for coating samples before electron microscopy. The Cressington 208 iridium sputtering tool provides very smooth, conformal coatings which are free of the grain structure found in films of Au or Au-Pd. Chromium would also be a good choice for coating SEM samples, but iridium oxidizes much more slowly, and so has an advantage over fine-grained chromium films.
A sputter coater for gold is located next to the chromium system. Gold is used for coating electron-beam resist before lithography, but is not a good choice for SEM samples.
Hitachi IM4000 ion mill
The Hitachi IM4000 can be used for cross-sectioning samples (usually for SEM viewing) or for polishing surfaces. This ion mill uses a knife edge to mask the ion beam, creating a straight cut. The sample stage is easily reconfigured for polishing the sample, by milling at a glancing angle. The polishing mode can also be used for thinning TEM samples. Operating at up to 6kV, the ion current is much higher than that of the Fischione 1050, but the spot size is also much larger.