Electron beam lithography with negative tone resist for highly integrated silicon quantum bits

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Electron-beam (EB) lithography is crucial for fabricating silicon quantum devices.
• Understanding and correcting proximity effects is essential for high-resolution EB lithography.
• Large-scale integration of quantum devices requires advanced lithography techniques.

Purpose of the Study:

• To develop and optimize EB lithography process technologies for silicon quantum devices.
• To investigate and mitigate proximity effects in EB lithography for complex structures.
• To enable the fabrication of highly integrated silicon quantum devices.

Main Methods:

• Utilized a point-beam EB system with maN 2401 negative tone resist.
• Optimized pre- and post-exposure bake temperatures for fine pattern formation (~20 nm).
• Employed EB process simulation to estimate dose distribution and correct proximity effects, including the mid-range effect.

Main Results:

• Achieved ~20 nm fine patterns with minimal line-edge roughness.
• Successfully fabricated complex Si-on-insulator device patterns with varying feature sizes.
• Validated EB process simulation by reproducing experimental resist patterns, incorporating the mid-range effect.

Conclusions:

• Developed effective EB lithography process technologies for silicon quantum devices.
• Demonstrated a method for correcting proximity effects, crucial for complex device layouts.
• The findings are expected to accelerate research and development in silicon quantum devices.