Advanced fabrication process for combined atomic force-scanning electrochemical microscopy (AFM-SECM) probes

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Focused Ion Beam (FIB) milling is crucial for specialized scanning probe microscopy (SPM) probe fabrication.
• Fabricating combined atomic force-scanning electrochemical microscopy (AFM-SECM) probes typically involves multiple, time-consuming milling steps.
• Developing efficient and reproducible methods for creating these bifunctional probes is essential for advancing SPM applications.

Purpose of the Study:

• To report an advanced software-controlled FIB patterning process for fabricating combined AFM-SECM probes.
• To present a semi-automated FIB milling routine for high-reproducibility fabrication of bifunctional probes.
• To evaluate different insulation materials and their impact on probe performance and stability.

Main Methods:

• Utilized a software-controlled focused ion beam (FIB) system with an advanced patterning routine.
• Developed a semi-automated FIB milling process for complex multi-layer/multi-material probe structures.
• Employed cyclic voltammetry for electrochemical characterization and AFM-SECM imaging for performance testing.
• Investigated Parylene-C and SixNy as insulation materials.

Main Results:

• Demonstrated a single milling routine for complex bifunctional probe fabrication, significantly reducing time and cost.
• Achieved high reproducibility in fabricating combined AFM-SECM probes.
• Evaluated the influence of insulation materials (Parylene-C, SixNy) on milling, electrochemical behavior, and long-term stability.
• Assessed the impact of material composition and layer sequence on probe shape and properties.

Conclusions:

• The developed semi-automated FIB milling process offers a streamlined and reproducible method for fabricating combined AFM-SECM probes.
• This approach has the potential for wafer-level processing, enabling mass production of these advanced probes.
• Material selection and structural design are critical for optimizing the performance and stability of bifunctional AFM-SECM probes.