Multitip

A multitip, in scientific instrumentation, refers to a device or probe that integrates multiple individual tips for contacting or interacting with a target surface. The tips may be used simultaneously or sequentially to perform complementary measurements or manipulations. The term is commonly used in nanoscale microscopy and electrical metrology.

In scanning probe microscopy, multitip systems place two or more independent tips on a single scanning head. These multi-tip scanning tunneling microscopes (STM) or atomic force microscopes (AFM) enable four-point electrical measurements, local lithography, and correlated imaging by contacting several spots on a sample without moving the stage. Such configurations are used to study electronic transport, nanoscale conduction, and to implement in situ tip-based manipulation.

In electrical metrology, multitip probes provide four-point probe functionality at the nanoscale, improving measurement accuracy by separating current injection from voltage sensing. They are essential for characterizing sheet resistance of thin films, graphene, and other 2D materials, where contact resistance and geometry can dominate in conventional two-point measurements.

Implementation challenges include precise tip alignment, mechanical drift, crosstalk between tips, and maintaining tip stability during measurement. Tip fabrication often uses materials like platinum-iridium or tungsten, and tips may be individually actuated and controlled by feedback loops. Instrumentation may require ultra-high vacuum and vibration isolation for high-resolution STM-based multitip variants.

Multitip configurations are primarily used in research settings and are not common consumer tools. They provide capabilities for nanoscale electrical measurements, nanofabrication, and advanced materials characterization.

See also: four-point probe, scanning tunneling microscope, atomic force microscope, nanoscale metrology.