On-tip sub-micrometer Hall probes for magnetic microscopy prepared by AFM lithography

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• Scanning probe microscopy techniques like SHPM and MFM require highly sensitive and spatially resolved magnetic field sensors.
• Existing Hall probes often lack the necessary sub-micrometer dimensions for advanced nanoscale magnetic imaging.

Purpose of the Study:

• To develop sub-micrometer Hall probes for enhanced spatial resolution in scanning hall probe microscopy (SHPM) and magnetic force microscopy (MFM).
• To integrate two distinct fabrication technologies for creating these advanced nanoscale sensors.

Main Methods:

• Fabrication of approximately 9-micrometer Hall probes on GaAs pyramids using wet-chemical etching and non-planar lithography.
• Downsizing planar Hall probe active areas to sub-micrometer dimensions via local anodic oxidation with an atomic force microscope.
• Combining these techniques to produce sub-micrometer Hall probes on high-aspect-ratio mesas.

Main Results:

• Successful fabrication of Hall probes with dimensions down to the sub-micrometer range.
• Evaluation of the noise and magnetic field sensitivity of the developed planar sub-micrometer Hall probes.
• Demonstration of a combined technology for producing Hall probes suitable for SHPM and MFM.

Conclusions:

• The developed technology enables the creation of sub-micrometer Hall probes essential for next-generation nanoscale magnetic imaging.
• This advancement is critical for improving the resolution and capabilities of SHPM and MFM techniques.
• The integration of wet-chemical etching, non-planar lithography, and atomic force microscope-based local anodic oxidation provides a pathway for fabricating advanced magnetic sensors.