Liquid metal ion gun

A liquid metal ion gun is an ion source that generates a focused ion beam (FIB) using ions extracted from a liquid metal, most commonly gallium (Ga+ ions).

Liquid metal ion sources are widely used in high-resolution analysis applications, but are also suitable for precise ion beam applications such as cutting, milling or nanofabrication.

They consist of a liquid metal reservoir that feeds a blunt tungsten tip from which a strong electric field extracts ions in the form of an electrospray. The ions are accelerated and focused onto the sample using electrostatic lenses. The generated monatomic ion beams respectively ion beams with small clusters, such as ^Au+, ^Ga+ and ^Au3+ are characterized by a high current density and spot sizes below 100 nm.

LMIS are more suitable for analyzing hard materials, as their small, high-energy ions can penetrate far below the surface before they release their energy. The damage this causes can make depth profiling unreliable for sensitive samples. LMIS are also used for ion implantation in the manufacture of semiconductor components and in metal finishing.

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