SPI Supplies^® Brand Silicon Nitride Membrane Window Grids for TEM

SPI Supplies was the first in the world to truly commercialize and promote silicon nitride membrane window grids for TEM grid applications. While individual researchers at various worldwide locations had tried making them on their own, and a few in fact did succeed, it was clear that there could be a substantial business opportunity to make these grids in high volume, enabling low unit costs, which can then be passed on to our customers as lower prices, and for most customers, at prices that are far far lower than they could make them themselves.

Don't be fooled by newcomers!

SPI Supplies has had years of experience working with researchers to develop the "perfect" membrane window grid. Not only that, but we have invested enormous amounts of money and time in the characterization of the membrane windows, information that can be at times very very important for many research applications. We know what membrane thickness would be the best for different applications. We know all about temperature stability. We can supply electrical resistivity information. We can supply optical transparency information. Our low stress membranes are so good and so robust, that when used as x-ray windows, we will guarantee them against vacuum failure. Our membranes can also withstand cleaning for re-use, however the main reason we don't recommend reusing the membranes is because of the possibility of nanoparticle cross-contamination, one sample to another.

But perhaps the best reason to "stick with SPI" is the worlds largest selection of membrane window sizes and membrane thickness, all in TEM grid dimensions, and available in small and convenient packs of ten grids. This way a researcher can experiment with grids of different membrane thickness and is not bound to restrict their work to a particular membrane thickness. Indeed, much of the excitement today is with the use of our ultra thin 20 and 30 nm thick membranes. True, these are fragile, but they are sufficiently robust for one to conduct most experiments.

Membrane Window Thickness Measurements:

While for many users of these membrane windows, thickness of the membrane is that not important for many, it is extremely important and we have developed our own special test methods for making the membrane thickness measurement.

Flatness and Smoothness:

Those working at the forefront of nanotechnology and who are using the SPI Supplies Brand of silicon nitride membrane window grids for studying self-assembling arrays are greatly concerned about "smoothness" which is part of the overall subject of "surface texture" which is defined in ANSI/ASME B46.1 as relating to surface roughness, waviness and lay". For the silicon nitride windows, the "waviness" or "flatness" is directly related to the flatness of the starting silicon wafer since the membrane itself is low stress nitride. But it is the question of surface roughness (or smoothness) that is of concern to those studying self-assembling arrays. We had an independent laboratory procure grids from SPI Supplies and from a competitive source and we can state with confidence that the surface smoothness of the SPI Supplies brand of membrane window grids is superior in every conceivable way. The RMS (R_g) is ~ 0.70 nm and the Mean Roughness (R_a) is ~ 0.47 nm. A more extensive description of the laboratory's finding will answer most other questions. Note of caution: We present these numbers in good faith but they are not presented from the perspective that they are product specifications. We believe they are fairly representative of current production and that specific lots might be slightly better or slightly worse. We also offer comparison information about surface roughness of other supposedly "smooth" surfaces.

The SPI Supplies Silicon Nitride Membrane Window Grids are available with windows that are both continuous film low stress silicon nitride and also, perforated. The windows are available in both square format as well as a slot format. We have them available from 1000 nm down to 20 nm, as standard products, usually in stock but if not, normally the waiting time is very short. And remember, with SPI Supplies, you (almost) never ever had to order gigantic quantities when all you want to do is a few experiments. We have a vast inventory of membrane window grids in stock, on the shelf, ready for immediate shipment to customers wherever in the world they might be......

Handling and storage of these grids:

All of the SPI Supplies Brand of membrane window grids, silicon nitride or silicon oxide, can be handled and treated like conventional TEM grids. They can be picked up with the same high precision tweezers that are used for picking up conventional grids. And they can be stored in the same kinds of grid boxes, either SPI Supplies Brand or BEEM® Brand that have been used for conventional grids. For those working with nanoparticles which because of their higher surface area relative to more conventional samples, are more "reactive", we suggest storage in an inert atmosphere, and using the SPI-Dry™ Sample Preserver Capsules.

You can trust the SPI Supplies Brand of membrane window grids:

SPI Supplies was the first firm to make available commercially, membrane window grids for TEM applications. Today, literally hundreds of researchers worldwide are using the SPI Supplies Brand of membrane window grids. And as the results from these workers get published, we will attempt to keep a listing of such publications.