Ion

Select

Evolved to enable advanced nanofabrication with different ion species, it features unique universal ion sources, defining a new state of the art in FIB technologies.

Introduction

The IonSelect setup comes with a multispecies ion source consisting of a eutectic alloy containing various ion species. This liquid metal alloy ion source (LMAIS) replaces the Gallium (Ga) liquid metal ion source (LMIS) to make universal combinations containing light and heavy ions from a single source.

Multiple ions species for advanced nanofabrication, ion imaging and nano analytics

Key features

Benefits for applications

Easy switching between multiple ions from a single source within a few seconds while maintaining a stable ion beam

Tailored nanostructures

Meet the requirements of your application and use different ion species (m/q) to optimize patterning resolution and sputter yield.

Enhanced ion
imaging

Use light ions for high-resolution ion microscopy with minimal sample damage for surface-sensitive imaging.

Vast number of application fields

Seamlessly access to various ions for a range of applications including direct milling, ion implantation, and masking.

Optimized sample patterning

Select the best ion species for your particular use case to avoid either contamination or make use of intended ion implantation.

Application-specific primary ion beams for SIMS

Choose the best primary ion to optimize sputter yield, spatial resolution, depth resolution, or ionization yield. IonSelect provides application-specific primary ions for optimized SIMS nanoanalytics.

Technical details

A new benchmark for nanoengineering applications

Source

Unlike Gallium, eutectic alloys used in LMAIS are solid at room temperature and require heating for operation. Typically, eutectics need only a few hundred degrees Celsius for liquefaction, significantly lower than the melting point of the alloy’s pure components. This makes LMAIS ideal for producing various ions with moderate source heating.

Both Ga sources and LMAIS share a common mechanical setup and working principle: a reservoir containing Ga or eutectic alloy is connected to a metallic needle. Ion emission is initiated by applying an extractor voltage to create a strong electric field near the tip.

Schematics of Ga FIB ion emission (left) and schematics of LMAIS FIB including source heating (right)

Quick ion toggling with IonSelect technology for FIB:
Left: Ion image of chessy sample generated by Bismuth focused ion beams. Ions are quickly changed from Bismuth to Lithium.
Right: Ion image of the same sample area generated by Lithium ions without offset and without beam settling time.

Wienfilter

Since the liquid metal alloy ion source emits various ions or clusters of different charge states simultaneously, switching between multiple ion species (m/q) is necessary. This is easily achieved by utilizing an ExB filter system, maintaining high resolution nanoFIB performance. A permanent magnet, located outside the vacuum column, provides a constant B field to eliminate hysteresis effects.

Adjusting voltages changes the required electrical field, facilitating separation of different (m/q) ions. Quick, reliable toggling between different ion species, clusters, or charge states is possible without mechanical realignment, as only the electrical field of the ExB filter needs adjustment for ion switching.

ExB filter setup to separate ions of different mass and charge

Use case

A good example of using both light and heavy ions from a single source in nanofabrication is the fabrication of bow ties. In the first step, heavy bismuth ions are used to remove a large volume of material and retain only small rectangles. In the second step, light lithium ions are used to refine the structure and carve out the bow ties. The entire process can be run automatically, with quick and reliable switching between ion species. This approach leverages the high sputter yield of bismuth and the high resolution of lithium, resulting in a faster and more accurate fabrication process.