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Electron Microscopy Facility

Sample Prep Tools

Sputter Coaters

Two sputter coaters available for non-conductive or beam sensitive samples. Most of our SEMs allow for Variable Pressure imaging and can use low accelerating voltages, but in some cases higher quality or higher resolution imaging requires a thin coating (~1-10 nm).

  • Reduced beam damage for sensitive specimen
  • Increased conduction reduces sample charging
  • Minimizes thermal damage from e- beam
  • Improved edge resolution by reducing beam penetration
  • All coatings have a higher electron yield and will increase signal to noise during imaging.
  • Coating with lower atomic numbers is best for BSE imaging while higher atomic numbers is better for SE imaging
Target Grain (nm) Max Mag Sputter Rate Pros Cons
Platinum 2-3 50k Lower sputtering rate than gold Can show “stress cracking” in presence of oxygen Most commonly used Finer grains than Au or Au/Pd
Gold 10-12 10 k Fast sputtering Typically has large islands / grains Fast Sputter Does not oxidize under air exposure
Gold / Palladium alloy (60/40 and 80/20) 4-8 25k Slightly slower sputter rate than pure Au Smaller grain size than gold
Amorphous Carbon No crystalline structure Appropriate for mag down to TEM Lower conductivity than the metal options Best for EDX analysis. C X-ray peak does not overlap other elemental peaks
Prices for each target is shared (here)

SEM images sputtered 2nm thick on glass. Imaged at 10 keV. Image width 140 nm.SEM images sputtered 2nm thick on glass. Imaged at 10 keV. Image width 140 nm.
Heu, R., Shahbazmohamadi, S., Yorston, J., & Capeder, P. (2019). Microscopy Today, 27(4), 32-36.

Sample specifics

This is especially useful for biological samples. It can also help with samples like plastics that are sensitive the to the energetic SEM beam.

  • Non-conductive samples accumulate electrons due to charging.
  • Charging artifacts include sample shifting, white or bright spots, swelling, and raster shifts.
  • Samples can also be sensitive to the heat imparted by the SEM beam.


Once the sample is coated the atomic number contrast visualized on SEM is lost.

Users must test coating parameters to identify optimal conditions for each sample type. We have a standard procedure that is useful for a wide variety of material and can be used as a starting point.

Non-ideal coatings can add false topography, grain structures, or islands.

Anatech Hummer 6.2 Sputter Coater

This uses cold temperature deposition where ions dislodge metal atoms from the target. These atoms uniformly coat specimens even with irregular shape or surface variability without causing thermal damage. Coating thickness is controllable, repeatable, and easily controlled.

  • Plasma mode : Outgas and clean sample before applying coating
  • Etching mode : Removes non-bonded surface material to provide better adhesion
  • Plating mode : Coats a specimen with chosen metal


Anatech CDS 2.2 Carbon Sputter Coater

Thermal evaporation of carbon under vacuum using a carbon rod. 100 amps of electrical current is passed between the rod producing resistive heating. Carbon is evaporated from the point and deposited on the sample surface. The vacuum removes oxygen, nitrogen, and water vapor from the coating chamber providing two key features

  • Reduced impurities and defects in the film
  • Reduced scattering creates an amorphous film of higher purity and density

Chamber can hold samples up to 3.25" diameter or 12 stubs


Resin Embedding for Sample Cross-Sections

A variety of resins and mold are provided for sample embedding of different shapes, sizes, and types of samples. Members with experience in these techniques can provide guidance for the best approaches for new samples. Listed is the typical process

  • Embed samples in resin mold
  • Section the resin to expose desired surface or cross-section with one of the techniques
    • Fracture / Freeze fracture
    • Microtome Sectioning
    • Cutting with abrasive saw
    • Cutting / Milling / Polishing with CleanMill Broad Ion Beam System
  • Polishing with Grinder/Polisher
  • Overnight ultra-fine polishing with Vibromet



ThermoFisher CleanMill Broad Ion Beam System

Argon Ion beam polishing for a pristine and artifact-free surface preparation for SEM. High throughput and automated for quick and easy sample preparation.

  • Rapid cutting / milling / polishing with the 16 kV Ar ion gun.
  • Ultra fine surface polishing from 100 V to 2 kV.
  • Cryogenic milling with LN2 cooling for beam sensitive materials.

System Parameters

Standard sample preparation : 30 mm (diameter) x 15 mm (height)

Cross section preparation : 90° slope: 10 mm x 10 mm x 3 mm

Dedicated optical microscope with CMOS camera 10x optical zoom and 120 x digital zoom


RMC Boeckeler PowerTome X

Ultramicrotome for producing semi and ultra thin sections for TEM, SEM, and TOF SIMS.

  • Sections cut to thicknesses of 5 nm – 10 μm
  • Cryo- sample preparation is available with this system

Table Top Saws

TechCut 5x Precision High Speed Saw

Precision high speed saw used to cut samples down to the appropriate size for analysis. Mainly this is used to prepare cross-sections for analysis.

  • Diamond blade
  • Water cooled with Allied Cool3 cutting fluid (MDEA and DEG monobutyl ether)
  • Approximate sample size 5” x 5” x 3”


Buehler Samplmet 2 Abrasive Cutter

Coarse cutter for large samples that are too big to be prepared for resin embedding. Water cooled with a cutting fluid.



Allied MetPrep3 Grinder Polisher with Power Head


Buehler AutoMet 250 Grinder Polisher

Semiautomatic polishers for preparing fine clean surfaces for analysis. Both are central force for up to 6 sample mounts – a minimum of 3 must be prepared at once for balance. A series of steps are used to grind and then polish the samples starting with larger grain and moving to the finest smallest polishing fluids. Provided is a wide range of procedures with detailed recipes for a wide variety of sample types from metals to polymers.

  • Samples are first ground to a flat plane with sand paper
  • Monocrystalline Diamond Suspension 9 μm for rough polishing
  • Diamond paste with the MetaDi fluid 3 μm
  • Nanocrystalline diamond suspension 1 μm
  • Fine polishing utilizes 0.05 μm with either an alumina or colloidal silica suspension


Buehler VibroMet 2 Vibratory Polisher


Buehler VibroMet 1 Vibratory Polisher

The last step for high quality polished surfaces for EBSD are prepared through chemo-mechanical polishing. All minor deformations are removed and an exceptionally flat surface can be prepared overnight with horizontal vibration at 7200 cycles per minute with minimal mechanical stress.

  • Colloidal silica suspension 0.05 μm MasterPrep polishing suspension
  • 18 specimens can be prepared simultaneously
  • Works for mixed materials and non-homogenous specimens

Zeiss Axiovert 25 Inverted Metallurgical Microscope with Camera

Used to visualize and image cut and polished EBSD samples. Can collect high quality images and visualize impurities or defects in metallurgical cross-sections.


Meiji MT Series Compound Microscope with Infinity 2 CMOS Camera

Visualize and image SEM, TEM, XPS sample preparation.


Sample Cleaner ZONETEM

Powerful desktop UV sample cleaner / desiccator removes hydrocarbon contamination of TEM and STEM grid specimens. Provides cleanest surface for the best possible data analysis.

  • Cleaning and storage of up to 3 TEM holders
  • Vacuum-controlled UV irradiation
  • Gentle and fast



Desiccators are available at each microscope for sample storage after sample prep is completed.