Phase masks for electron microscopy fabricated by thermal scanning probe lithography

Area of Science:

• Electron microscopy
• Nanofabrication
• Materials science

Background:

• Nano-structured phase masks are crucial for advanced electron beam shaping.
• Conventional fabrication using focused ion beam milling leads to gallium implantation, affecting mask performance.
• Developing alternative fabrication methods is essential for high-quality electron optics.

Purpose of the Study:

• To fabricate silicon-nitride phase masks for electron beam shaping.
• To overcome the limitations of gallium implantation associated with focused ion beam milling.
• To demonstrate the generation of electron vortex and Bessel beams using the novel phase masks.

Main Methods:

• Fabrication of silicon-nitride phase masks using thermal scanning probe lithography.
• Integration of wet and dry etching techniques for precise pattern transfer.
• Characterization of fabricated phase masks and demonstration of electron beam shaping capabilities.

Main Results:

• Successful fabrication of silicon-nitride phase masks without gallium implantation.
• High accuracy and control over the nanostructure pattern and depth achieved.
• Demonstrated generation of electron vortex and Bessel beams, confirming mask functionality.

Conclusions:

• Thermal scanning probe lithography offers a superior alternative for fabricating electron phase masks.
• The developed method provides precise control and avoids detrimental ion implantation.
• This advancement enables enhanced electron beam shaping for advanced microscopy and lithography applications.