Download a PDF Version

Amorphous Silicon TEM Windows:
Half the Chromatic Blur and No Organic Contamination

A comparison analysis of the thinnest amorphous carbon and 5 nm amorphous UltraSM® Silicon TEM Windows revealed that UltraSM® Silicon TEM Windows:

  • Yield half the inelastic scattering of ultra-thin amorphous carbon
  • Are 35%+ thinner
  • Tolerate aggressive plasma cleaning and high-beam currents


These results were obtained through a grant program at Cornell University in collaboration with
Dr. David Muller, Associate Professor of Applied and Engineering Physics

Comparison of UltraSM® Non-Porous Silicon TEM Windows to the thinnest commercially available amorphous carbon grids reveals key differences for TEM imaging and analysis. UltraSM® Silicon TEM Windows yield half the inelastic scattering of ultra-thin amorphous carbon and are more uniformly thin. Combined with their tolerance for high-beam current and plasma cleaning, UltraSM® Silicon TEM Windows enable the preparation of higher quality samples, leading to improved imaging and reduced instrument time.

Comparison of Amorphous Silicon and Amorphous Carbon

A comparative analysis of electron energy loss spectroscopy (EELS) was performed at Cornell University by Dr. David Muller, a leading researcher in transmission electron microscopy. The analysis compared 5 nm amorphous UltraSM® Non-Porous Silicon TEM Windows with the thinnest commercially available amorphous carbon TEM grids (advertised as 3 nm thick). The spectral data shown below reveal two important distinctions:

  • Thickness: The ultra-thin amorphous carbon grids are 5-10 nm thick (2X to 3X thicker than advertised), while the amorphous UltraSM® Silicon are 3.5-5 nm thick.
  • Inelastic Scattering: The spectra reveal two-times less inelastic scattering of the electron beam within amorphous UltraSM® Silicon compared to amorphous carbon. Note the two-fold greater broadening of the spectrum from amorphous carbon, leading to twice the chromatic blur for the inelastically scattered electrons.

Figure 1: Electron Energy Loss Spectroscopy Analysis of 5 nm Amorphous UltraSM® Silicon (a-Si) and 3 nm Amorphous Carbon (a-C) EELS spectra were recorded on a 200 keV FEI Tecnal F20 and normalized to equal zero peak intensities. The sample thickness, t, can be extracted from the ratio of the inelastic/ elastic scattering if the inelastic mean free path, λ , is known. For a-C, t/λ = 0.1 and t = 10 nm. For a-Si, t/λ = 0.05 and t = 6.5 nm. Inelastic mean free paths, λ, were calculated using equation 5.2 from Egerton (1996)
1. R.F. Egerton, "Electron Energy-Loss Spectroscopy in the Electron Microscope", 2nd ed., Plenum, NY (1996).


Effectively three times thinner with reduced inelastic scattering, 5 nm amorphous UltraSM® Silicon TEM Windows help minimize chromatic blur, improve image resolution, and offer improved contrast relative to the best amorphous carbon TEM grids.


Figure 2: Representative images of gold nanoparticles imaged on 5 nm UltraSM® Silicon; plasma cleaned for 120 seconds prior to imaging. (Click on individual images to view full-resolution)

The pure silicon composition of UltraSM® Silicon TEM Windows improves substrate tolerance for high-beam currents and offers stability against vigorous plasma cleaning. In addition, the absence of a carbon background simplifies the materials analysis of carbon-containing materials using EDX and EELS. Any organic signatures are a direct reflection of the composition of the sample.

Ideal Substrate for High-Resolution Imaging and Analysis

These properties improve sample quality to a great extent, potentially reducing hours of costly TEM time. As a result, UltraSM® Non-Porous Silicon TEM Windows are an ideal sample substrate for high-resolution imaging and for high-beam current analyses such as EDX and EELS.