Which Silicon Nitride Membrane is Better for Your Research | 8 tips

What is a silicon nitride membrane?

Silicon Nitride is the most popular X-ray microscopy material due to its wide availability and ease of processing into individual membrane. Silicon Nitride has the conventional stoichiometry of Si3N4 and an intrinsic stress of about 1 GPa. Silicon Nitride (SiN) TEM window grids have a strong, flat, uniform silicon nitride membrane and are widely used as a stable viewing platform for TEM, SEM, Cryo-EM, AFM, Raman, XRD, and other equipment to meet the needs of researchers who wish to observe the microstructures and properties of samples at high resolution. Applications include nanoparticle imaging, quantitative carbon analysis, biological and chemical experiments, and crystal growth studies.

SiN TEM window grids maintain good performance even under harsh laboratory conditions, resulting in an ideal balance between imaging resolution, chemical stability and mechanical strength. Since they are also highly temperature resistant, they can be used for nanotechnology experiments on the membrane itself over a wide temperature range, etc.

8 tips for silicon nitride membrane

The mechanical stability of silicon nitride membrane allows a range of microscopy techniques such as TEM, SEM and AFM to be used for a variety of nanotechnology experiments. Cells, fibers, particles, etc. can be mounted directly on the support membrane for observation.

They are available in different window sizes on silicon support frames to fit standard 3 mm TEM mounts, and the membranes range in thickness from 20 nm to 500 nm. Silicon Nitride membrane are manufactured under clean room conditions and chemically cleaned prior to packaging. Typically, 10 silicon nitride membrane windows are packed in a grid box.

Researchers can look at eight dimensions when selecting silicon nitride membrane windows, including frame size, film thickness, number of windows, window size, stress profile, cleanliness, flatness, and coating. Several of these dimensions are briefly described below for your reference.

1. External frame sizes

The conventional outer frame size for synchrotron radiation silicon nitride thin membrane windows are 5.0, 7.5, and 10 mm, and for transmission electron microscopy (TEM) and scanning electron microscopy (SEM) silicon nitride thin membrane windows are 3x3 mm.

2. Nitride thickness

Standard sizes range from 10 nm to 200 nm, but YW MEMS can respond quickly to customized design requirements and are very popular.

3. Number of Windows

In addition to single pane silicon nitride dies, custom windows consisting of multiple films on a single frame can be supported for experimental separation or to improve the stability of large area films.

4. Window size

Window size determines the amount of electron flux that can pass through the window and reach the sample. Smaller window sizes can provide higher imaging resolution, but may also result in reduced signal intensity. For general imaging and analysis, larger window sizes are preferred, while smaller aperture sizes are recommended for high resolution imaging. Common window sizes applied to TEMs range from 0.1 mm to 1 mm.

5. Stress conditions

There are many ways to prepare silicon nitride film, such as low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), but the silicon nitride film obtained by the traditional method is generally in some kind of stress state, and the existence of stress will weaken the insulation, passivation, sealing and other effects of silicon nitride film, and also affect the performance of semiconductor devices, so it is particularly important to control the stress of silicon nitride film. Therefore, the control of stress in silicon nitride films is particularly important.

In biological research, it is necessary to select silicon nitride membrane windows with low stress to avoid damage to the sample. In materials science research, a silicon nitride window with higher stress is required to obtain more accurate results. YW MEMS can support customized silicon nitride membrane stress from 0-1500Mpa.