Coatings and Coating Materials
Continuous Film Coatings
Film coatings are chosen by their stability needed. One factor is the thickness of the film. The thicker the more stable they are. On the opposite side thicker films show more undesirable electron interaction. Combined films (Formvar/Carbon) offer the highest stability.
A thin film of pure formvar resin. The thickness range is as follows:
- Standard: Approx. 10nm
- Ultra-Thin (UL): 5-6nm
- Thick (TH): 15-20nm
- Extra Thick (ET): 25-50nm
A thin film of pure carbon deposited on one side of the grid. The thickness range is from 3nm to 30nm. Pure Carbon Films are mechanically not as stable as Formvar Films. On the other hand they show better electrical- and heat conduction in the electron beam.
The thickness range is as follows:
- Standard: Approx. 5-6nm
- Ultra-Thin (UL): 3-4nm
- Thick (TH): 10nm
- Extra Thick (ET): 20-30nm
A formvar coated TEM grid, stabilized with evaporated carbon film. This type of coating is excellent for specimen support, especially for ultra thin sections. The thickness ranges from 5-50nm formvar and 1-30nm carbon. For detailed information see description.
Formvar/Carbon film thickness ranges:
|Option||Name||Formvar Film||Carbon Film|
|Extra Thick||Option A||EA||25-50nm||1nm|
|Extra Thick||Option B||EB||25-50nm||3-4nm|
|Extra Thick||Option C||EC||25-50nm||20-30nm|
Formvar/Silicone Monoxide Film
A formvar film stabilized with a thin film of Silicone monoxide. Silicone monoxide produces a desirable support film because it offers low background contrast and it is stable under the electron beam and it is more hydrophilic than carbon film.
The DuraSiN™ Film support grids are composed of two materials. The area for specimen observation is fabricated from chemically robust, low-stress, planar silicon nitride films and this area is supported by a rigid silicon frame where the frame thickness available for these products ranges from 200 – 600 µm. The DuraSiN™ Film support grids provide a cost-effective and durable platform for sample preparation, cleaning, imaging and analysis. Perfect for the analysis of colloids, powders, aerosols and polymers. The DuraSiN™ Film provides durable, non-organic, low scatter substrates for quantitative TEM and X-ray analysis at affordable prices. DuraSiN™ Film substrates are fabricated from high quality, low-stress silicon nitride and supported on a rigid silicon substrate. DuraSiN™ Film products are robust to most cleaning procedures, including acetone, alcohol and oxygen plasma/UV ozone. Products are available in sizes ranging from standard TEM (2.65mm diameter) to greater than 10mm for x-ray applications.
Beryllium Support Films
A deposition of 250 Angstroms thick Beryllium onto the 0.005" thick, 25x25mm squares of a Cu substrate. The Beryllium can be removed by dissolving the substrate in nitric acid (50:50). The Beryllium film will then be removed from the acid, washed in distilled water and mounted on TEM grids. A Beryllium support film will reduce background interference to a minimum and it is particularly useful where analyses for C or Si are required, so that these alternative supports cannot be used. Another advantage of the Beryllium support is its very fine grain size which produces a very sharp ring pattern for in-situ calibration.
Holey Film Coatings
Irregular Holey Film Coatings
Lacey Carbon Film
This carbon coated film on a broken pattern consists of woven-mesh-like holes of different sizes and shapes. This type of pattern provides support but does not interfere when observing specimen sections.
Holey Carbon Film:
A thin piece of carbon with numerous round holes of various sizes.
Regular Film Coatings
C-flat Holey Carbon Film
C-flat™ is an ultra-flat, holey carbon-coated TEM support grid mostly used for cryo-TEM. Unlike competing holey carbon films, C-flat™ is manufactured without plastics, so it is clean upon arrival and the user has no residue to contend with.
C-flat™ provides an ultra-flat surface that results in better particle dispersion and more uniform ice thickness. All C-flat products are fully specified by 4 parameters: the hole diameter and pitch of the holey carbon film and the material type and mesh size of the TEM grid. Applications (TEM, cryo TEM, cryo-ET, SPA, automated TEM).
C-flat™ provide a variety of different pattern and hole diameters/distances:
Quantifoil – Holey Carbon Films
QUANTIFOIL ® is a perforated support foil with pre-defined hole size, shape and arrangement. It has advantages in electron microscopy (EM) or low-energy electron point source (LEEPS) microscopy when compared with conventional holey film. QUANTIFOIL ® is offered with circular and square, orthogonal arranged holes. Films with different hole sizes and bar widths are available. Carbon is the standard material that makes the foil. QUANTIFOIL® is a superior quality of holey carbon film, which facilitates the use of automation in TEM.
DuraSiN™ Mesh support grids are also fabricated from chemically robust, low-stress, planar silicon nitride films and are supported by a rigid silicon frame. However, DuraSiN™ Mesh has a regular array of small, dense holes fabricated across the observation area thereby providing truly electronbeam transparent regions for specimen imaging and analysis. DuraSiN™ Mesh support substrates offer the unique combination of an inorganic support film and regions completely transparent to an electron beam. These two features provide the microscopist and micro-analyst with unparalleled capability for imaging and analysis. Like other holey or lacey support films, DuraSiN™ Mesh support substrates provide regions completely unobstructed by the support film. However, the fact that the DuraSiN™ Mesh is made from inorganic silicon nitride provides the ability to thoroughly clean (e.g. with an aggressive oxygen plasma) a specimen already fixed to the support substrate and to assure that the imaging and analysis is done only upon on the specimen rather than unintended contamination.