Superconducting Diamond on Silicon Nitride for Device Applications.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Chemical vapour deposition (CVD) grown nanocrystalline diamond is crucial for advanced device fabrication.
• Optimizing diamond growth on silicon nitride substrates is essential for specific device architectures.

Purpose of the Study:

• Investigate the impact of pre-growth surface treatments on silicon nitride for nanocrystalline diamond growth.
• Control surface charge and functionality of silicon nitride to optimize diamond seeding.

Main Methods:

• Analyzed silicon nitride surface properties using Zeta potential measurements and X-ray photoelectron spectroscopy (XPS).
• Evaluated three common cleaning methods as pre-growth surface treatments.
• Grew boron-doped nanocrystalline diamond thin films via CVD on treated substrates.

Main Results:

• Oxygen plasma treatment yielded optimal surface conditions for electrostatic self-assembly of diamond nanoparticle monolayers.
• Coalesced diamond films were achieved with oxygen plasma and solvent treatments; RCA-1 treatment resulted in pin-holing.
• Diamond films grown on oxygen plasma treated silicon nitride exhibited the sharpest superconducting transition, indicating minimal structural disorder.

Conclusions:

• Surface modification of silicon nitride substrates significantly optimizes diamond seeding and growth processes.
• Oxygen plasma treatment is a highly effective method for preparing silicon nitride for high-quality nanocrystalline diamond film deposition.
• Optimized diamond-on-silicon nitride interfaces are critical for fabricating high-performance diamond-based devices.