Nanostructure fabrication by ultra-high-resolution environmental scanning electron microscopy

Area of Science:

• Nanofabrication and Nanotechnology
• Materials Science and Engineering
• Surface Science and Engineering

Background:

• Electron beam induced deposition (EBID) is a maskless nanofabrication method with high resolution potential.
• Limitations of conventional EBID include beam spread, substrate charging, and unwanted film growth, hindering functional nanostructure fabrication.
• Existing methods struggle with precise control over nanostructure dimensions and morphology.

Purpose of the Study:

• To overcome the limitations of traditional EBID for fabricating functional nanostructures.
• To develop a method for precise control over nanostructure morphology using environmental scanning electron microscopy (ESEM).
• To demonstrate the fabrication of nanoscale gaps and the removal of surrounding films in EBID-deposited nanostructures.

Main Methods:

• Utilized environmental scanning electron microscopy (ESEM) for performing EBID and in-situ etching.
• Implemented ESEM imaging with a gaseous etch precursor to slim deposited nanostructures.
• Employed pre-etching techniques with stationary or scanned electron beams to create features before final imaging.

Main Results:

• Successfully eliminated charging artifacts at the nanoscale during EBID.
• Demonstrated the ability to tailor nanostructure morphology, including slimming of nanowires.
• Fabricated precise gaps (4-7 nm wide) in nanowires and removed surrounding thin films with nanoscale resolution.

Conclusions:

• ESEM-based EBID and etching provide a viable solution to overcome key limitations in nanofabrication.
• The developed process allows for direct visualization and precise control over nanostructure dimensions, limited by ESEM resolution (~1 nm).
• This technique opens new avenues for creating complex, functional nanostructures with high precision.