Nanoscale lithography with visible light: optical nonlinear saturable absorption effect induced nanobump pattern...

Area of Science:

• Nanotechnology
• Optics
• Materials Science

Background:

• Conventional lithography relies on short-wavelength lasers or charged particles for high resolution.
• Visible light lithography offers practical advantages like lower cost and simpler operation.

Purpose of the Study:

• To propose and verify a scheme for nanoscale lithography using visible light and nonlinear optical effects.
• To achieve nanobump pattern structures with high resolution.

Main Methods:

• Utilized the optical nonlinear saturable absorption effect in silicon (Si) thin films.
• Employed a gallium nitride (GaN) semiconductor diode as the visible light laser source.
• Verified the technique using a high-density digital versatile disk tester for direct laser writing.

Main Results:

• Theoretical simulations predicted a spot size reduction to approximately 1/12th of the original.
• Experimental verification yielded nanostructures with a size of approximately 80 nm.
• Achieved feature sizes approximately 1/10th of the optical diffraction limit.

Conclusions:

• The proposed technical scheme effectively enables nanoscale lithography with visible light.
• Nonlinear saturable absorption in Si thin films is a viable method for high-resolution patterning.
• This approach provides a cost-effective and practical alternative for nanostructure fabrication.