Conductive polycrystalline diamond probes for local anodic oxidation lithography

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Local anodic oxidation (LAO) lithography is a key nanofabrication technique.
• Tip material significantly influences LAO performance and resolution.
• Conductive polycrystalline diamond (PCD) probes offer potential advantages due to their properties.

Purpose of the Study:

• To characterize and compare local anodic oxidation (LAO) lithography using conductive monolithic diamond (MD) and diamond-coated (DC) tips.
• To evaluate the impact of tip material on lithographic linewidth and height.
• To assess the performance of PCD probes for fine LAO lithography.

Main Methods:

• Local anodic oxidation (LAO) lithography was performed using conductive MD, DC, diamond-like carbon-coated, and metal-coated silicon tips.
• Lithographic linewidth and height were measured as a function of tip bias and write speed.
• Tip performance was analyzed based on parameters like linewidth/height rate of increase (dw/dV, dh/dV), threshold voltage, and proportionality constants.

Main Results:

• Conductive DC tips produced wider and taller lines with higher dw/dV and dh/dV compared to metal-coated tips.
• MD tips exhibited a higher threshold voltage and resulted in significantly smaller linewidths and heights than metal-coated tips.
• Linewidths were inversely proportional to the log of write speed, with varying proportionality constants based on tip material.
• Line height showed a sigmoidal relationship with width, with MD probes achieving lower heights.

Conclusions:

• Conductive polycrystalline diamond (PCD) probes, particularly DC tips, demonstrate enhanced performance in LAO lithography.
• MD tips offer finer feature control with lower height and linewidth.
• The wear resistance and performance of PCD probes expand their utility in high-resolution LAO lithography.