Thin-Film Phase Plates for Transmission Electron Microscopy Fabricated from Metallic Glasses

Abstract

(M. Dries). AbstractThin-film based phase plates are meanwhile a widespread tool to enhance the contrast of weak-phase objects in transmission electron microscopy (TEM). The thin film usually consists of amorphous carbon, which suffers from quick degeneration under the intense electron-beam illumination. Recent investigations have focused on the search for alternative materials with an improved material stability.This work presents thin-film based phase plates fabricated from metallic glass alloys, which are characterized by a high electrical conductivity and an amorphous structure. Thin films of the zirconiumbased alloy Zr 65.0 Al 7.5 Cu 27.5 (ZAC) are prepared and their phase-shifting properties are tested. The ZAC-alloy film is investigated by different TEM techniques, which reveal a range of beneficial characteristics. Particularly favorable is the small probability for inelastic plasmon scattering, which is promising to improve the performance of thin-film based phase plates in phase-contrast TEM.

Charging of carbon thin films in scanning and phase-plate transmission electron microscopy

“…which is a common value for aC thin films [16,26,27]. The red crosses in Figure 6a show the expected phase shift evolution with the error bars reflecting the uncertainty in the inelastic MFP and the MIP.…”

Spherical aberration correction in a scanning transmission electron microscope using a sculpted thin film

“…Although a thicker design would allow stronger correction, it would also result in increased electron scattering and therefore a lower current in the corrected probe. This drawback could be compensated by enlarging the diameter of the corrector or by using a different material [27]. A thinner design would reduce scattering and increase contrast, but would provide less correction.…”

“…Our foil corrector can be fabricated in-house and implemented in an existing uncorrected electron microscope without changing the normal operating procedure. Other weaklyscattering materials [27], as well as thinner or fractured (modulo-) designs and spatial filtering at the sample plane, can be used to further reduce the effect of inelastically scattered electrons and to improve STEM image contrast. The concept can be extended to correction of additional aberrations by appropriately designing the thickness profile.…”

Phase plates in the transmission electron microscope: operating principles and applications

“…on-chip devices [94] and a specific PP holder including load locks for rapid PP exchange [95], were conducted to improve stability and to decrease contamination and charging of the PP. Several groups investigated the use of alternative materials, including Si and metallic glasses [50,58,96]. Metallic glasses may lower the relative amount of inelastic scattering in the PP due to a higher ratio of elastic to inelastic scattering [58].…”

“…Several groups investigated the use of alternative materials, including Si and metallic glasses [50,58,96]. Metallic glasses may lower the relative amount of inelastic scattering in the PP due to a higher ratio of elastic to inelastic scattering [58].…”