A practical guide for microdevice fabrication using a focused ion beam equipped with a flip-stage

Electrical and thermal transport measurements are essential for investigating the electronic properties of single crystal materials. While traditional methods rely on manual contact placement directly on as-grown crystals, they offer no control over sample shape and face severe limitations in resolution and reproducibility, especially when dealing with crystals smaller than one millimeter. Focused ion beam lithography has emerged as a powerful alternative, enabling the fabrication of mesoscale devices with nanometer-scale precision, control over geometry and crystallographic orientation, deposition of electrical contacts, and fabrication of minimally invasive probes. This work presents a practical guide to microdevice fabrication using a Focused Ion Beam system equipped with an in situ flip-stage. We detail a complete protocol for sculpting complex three-dimensional structures from single crystals, leveraging the flip-stage's rotational degrees of freedom to define device width, thickness, and shape with high accuracy. The guide addresses key challenges, such as ion-induced surface damage and redeposition, and discusses strategies for mitigation. We also describe the deposition of electrical contacts via ion beam induced deposition, optimizing contact geometry and current density to achieve low-resistance, reproducible electrical contacts. Finally, we showcase a range of fabricated devices, demonstrating how the freedom to define 3D geometries enables the creation of unconventional device shapes, supporting more incisive material characterization and device prototyping.