Nanoscale lithography via electron beam induced deposition

Area of Science:

• Nanolithography
• Electron Beam Induced Deposition (EBID)
• Materials Science

Background:

• Advanced nanolithography techniques are crucial for fabricating nanoscale devices.
• Electron beam induced deposition (EBID) offers high resolution but requires optimization for pattern fidelity and material selectivity.

Purpose of the Study:

• To investigate the resolution and characteristics of EBID using W(CO)(6) and C(10)H(8) for nanolithography.
• To evaluate the process for defining imaging and masking layers on silicon substrates.
• To demonstrate the fabrication of silicon nanowires with high fidelity.

Main Methods:

• Utilized EBID of W(CO)(6) and C(10)H(8) on polymethylmethacrylate (PMMA)-coated silicon (PMMA-Si) and bare silicon (Si) substrates.
• Patterned lines and dot matrices at various electron beam doses.
• Assessed material selectivity during dry development and reactive ion etching.
• Employed Monte Carlo simulations to correlate EBID scattering with resolution.

Main Results:

• Achieved high selectivity for W(CO)(x) on PMMA (no etching) and silicon (18:1 etch ratio).
• Demonstrated good selectivity for C(10)H(8) on silicon (21:1 etch ratio).
• Fabricated silicon nanowires with 13.5 nm resolution and 24.5 nm linewidth using a bi-layer approach.
• Achieved 33 nm silicon nanowire resolution using a single-layer EBID approach directly on silicon.

Conclusions:

• EBID of W(CO)(6) and C(10)H(8) is a viable nanolithography technique for high-fidelity pattern transfer.
• The bi-layer approach yields superior resolution, enabling the fabrication of sub-20 nm silicon nanowires.
• Resolution is dependent on electron beam dose and EBID scattering effects, predictable via simulation.