SPI Supplies Silicon Membrane Window Grids for TEM

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10 years ago, SPI Supplies introduced Silicon Nitride Membrane Window grids to the TEM world.

Now SPI Supplies introduces Simpore UltraSM^® silicon membrane windows, silicon membrane window technology changes the way researchers in the nanoscale world look at their samples.

Why Silicon?

The ability to utilize membrane technology using silicon provides certain advantages over silicon nitride and silicon oxide membranes. In addition, silicon film as thin as 5nm can be produces providing the greatest transparency in TEM applications.

Silicon membranes are available in both solid thin films and perforated amorphous films. The porous nanocrystalline silicon (pnc-Si) membranes are less than 20 nm. Despite this thickness, the membranes are extremely strong and robust with film supporting well over 1 atmosphere of differential pressure. This stability enables a wide range of applications and creates numerous opportunities in broad fields requiring size-based or charge-based separation of ions, molecules, or other nanoscale objects.

Features of Silicon membrane TEM Windows:

Unique Benefits of Silicon Membrane TEM Windows

• Simple and stable suspension of nanoscale materials across the pores for background-free imaging
• A convenient internal calibration signal for materials analysis studies
• Remarkable stability at high beam currents and high annealing temperatures
• Vigorous plasma cleaning of samples
• Easy preparation of aqueous samples due to a hydrophilic surface

Handling:

UltraSM^® TEM Windows are made with 5 to 15 nm thick pure silicon membranes, which are amazingly robust when dry. However, care must be taken when they are wetted. We recommend avoiding excessive drying steps and using alcohols or low viscosity solvents in place of water for sample preparation. Even though they are significantly thicker, similar precaution should be taken with nitride and oxide TEM windows. High salt solutions should also be avoided. If a salt solution is required, then a final rinse in de-ionized water is recommended to avoid depositing salt crystals on the window. Wicking of excess fluid with absorbent paper should be avoided if possible. Drying samples under light vacuum or in air is recommended. To avoid breakage, grids should be stored in the provided gel-pack and the grids should remain membrane-side facing up as packaged. We recommend handling grids using flat-sided plastic tweezers such our style K2A or K6.

Cleaning:

UltraSM^® TEM Window Grids are made of pure silicon and can be repeatedly plasma cleaned without degradation. They can also be cleaned by UV-ozone without degradation. However, UV-ozone will reduce water contact angle and increase surface wetting. The silicon membrane can form a thin native oxide layer when exposed to the atmosphere. If desired, this oxide layer can be removed with a 15 second wash in 1:100 hydrofluoric acid (HF). Prolonged treatment in HF will slowly etch the silicon membrane. Warning: HF should only be used by experienced personnel with the appropriate environmental protection. Please consult the HF manufacturer's MSDS.

Products

Silicon membranes are available in both continuous and porous membrane films. They come as a package of 10 in a Gel-Pak container for ease of handling.

Continuous

Continuous Films 200µm Thick Grids

Continuous films may be slightly wrinkled with approximately 5 micrometers or less deflection across 100 micrometers of travel. We have found that this is typically not problem for high-resolution imaging.

The surface roughness generally ranges from 200 to 300 picometers RMS as measured by AFM. This was found to be consistent in both porous and non-porous films.

Frame Thickness: 200µm
Film Type: Amorphous Silicon
Frame Size: Fits 3mm TEM Sample Holder
Package Size: 10 Grids

Membrane Thickness (nm)	Window Size	Number of Windows per Grid	SPI #	Each		In Stock
15 nm	100 x 100 µm Squares	9	US200-A15Q	$210.00		Yes
9 nm	100 x 100 µm Squares	9	US200-A09Q	250.00		Yes
5 nm	100 x 100 µm Squares	9	US200-A05Q	290.00		Yes
15 nm	100 x 1500 µm Slots	2	US200-A09L	250.00		No
9 nm	100 x 1500 µm Slots	2	US200-A15L	210.00		Yes

Continuous Films 100µm Thick Grids

We now can order the continuous flim in a 100µm frame thickness. These 100 micron frames should fit a wider range of TEM sample holders, allowing more users to take advantage of our Si grids.

Frame Thickness: 100µm
Film Type: Amorphous Silicon
Frame Size: Fits 3mm TEM Sample Holder
Package Size: 10 Grid

Membrane Thickness (nm)	Window Size	Number of Windows per Grid	SPI #	Each		In Stock
15 nm	100 x 100 µm Squares	9	US100-A15Q	$210.00		Yes

Porous

Porous Films 200 µm Thick Grids

Note: Membrane films are porous due to crystallization of silicon. Nanocrystals can appear as background and the best imaging occurs over the nanopores. Occasionally a pore may be found in a particular window that may be as large as 10 micrometers; these pores do not reduce the robustness of the films and may be useful for beam alignment.

Frame Thickness: 200 µm
Film Type: Porous Crystalline
Frame Size: Fits 3 mm TEM Sample Holders
Package Size: 10 Grids

Membrane Thickness (nm)	Window Size	Number of Windows per Grid	Max Pore Size	Percent Porosity	SPI #	Each		In Stock
15nm	100 x 100 µm Squares	9	~ 50nm	~5%	US200-P15Q	$250.00		Yes
15nm	100 x 1500 µm Slots	2	~ 50nm	~5%	US200-P15L	250.00		Yes