Electron-Beam Patterning of Vapor-Deposited Solid Anisole

Area of Science:

• Nanofabrication
• Materials Science
• Electron Beam Lithography

Background:

• Emerging ice lithography (IL) offers an alternative to conventional electron-beam lithography (EBL).
• IL utilizes cryogenic temperatures and vapor-deposited organic molecules as electron beam resists.
• Investigating novel resists is crucial for advancing IL capabilities.

Purpose of the Study:

• To systematically investigate electron-beam patterning of frozen anisole.
• To assess anisole's performance as an electron beam resist in ice lithography.
• To explore the influence of anisole's solid state on pattern quality.

Main Methods:

• Electron-beam patterning of vapor-deposited anisole films at cryogenic temperatures.
• Dose curve analysis to determine resist contrast and energy dependence.
• Control of anisole film morphology (crystalline vs. amorphous) by adjusting deposition temperature.
• Surface roughness analysis using atomic force microscopy.

Main Results:

• Anisole exhibits low contrast (∼1) with minimal dependence on beam energy (5-20 keV).
• A minimum line width of 60 nm was achieved at 20 keV, limited by apparatus vibration.
• Amorphous anisole films, formed below 130 K, yield smooth patterns with ∼0.7 nm roughness.
• Successful fabrication of nanoscale patterns on high-aspect-ratio silicon micropillars.

Conclusions:

• Frozen anisole is a viable electron beam resist for ice lithography.
• Controlling the amorphous state of anisole enhances pattern quality.
• This study demonstrates the potential of anisole for 3D nanofabrication using IL.