Diamond probe preparation for developing faster high-speed atomic force microscopy

Single-crystal diamond (SCD), an ultimate mechanical engineering material, offers exceptional potential for next-generation sensing and imaging systems; however, its nanoscale fabrication-particularly for ultrathin free-standing devices-remains challenging. Here, we propose a universal hybrid micro/nanofabrication strategy and demonstrate its capability through the fabrication of ultrashort, ultrathin SCD cantilevers that overcome key performance limits in high-speed atomic force microscopy (HS-AFM). By combining high-throughput angled laser micromachining with nanoscale focused ion beam refinement, we achieve precise geometric control while preserving crystallinity and nanometer surface flatness, with drastically reduced material removal and fabrication time. This approach enables the direct fabrication of free-standing SCD cantilevers with dimensions of ∼7 × 2 × 0.08-0.15 μm3. By integrating amorphous carbon tips via electron-beam-induced deposition, fully functional HS-AFM probes are realized. The fabricated probes exhibit resonance frequencies of 3.7-6.0 MHz-3-4 times higher than commercial quartz-like cantilevers-while maintaining spring constants suitable for soft-matter and biological imaging. Using the fabricated SCD probe, HS-AFM imaging of actin filaments achieved stable acquisition at 25 fps. This scalable and versatile method opens new opportunities for ultrafast HS-AFM and broadly enables high-performance diamond nanostructures for nanomechanical sensing and micro- and nanoelectromechanical systems.