Beams of electrons and ions are now fairly routinely focused to dimensions in the nanometer range. Since the beams can be used to locally alter material at the point where they are incident on a surface, they represent direct nanofabrication tools. The authors will focus here on direct fabrication rather than lithography, which is indirect in that it uses the intermediary of resist. In the case of both ions and electrons, material addition or removal can be achieved using precursor gases. In addition ions can also alter material by sputtering (milling), by damage, or by implantation. Many material removal and deposition processes employing precursor gases have been developed for numerous practical applications, such as mask repair, circuit restructuring and repair, and sample sectioning. The authors will also discuss structures that are made for research purposes or for demonstration of the processing capabilities. In many cases the minimum dimensions at which these processes can be realized are considerably larger than the beam diameters. The atomic level mechanisms responsible for the precursor gas activation have not been studied in detail in many cases. The authors will review the state of the art and level of understanding of direct ion and electron beam fabrication and point out some of the unsolved problems.

The focused ion beam (FIB) is a powerful tool for fabrication, modification, and characterization of materials down to the nanoscale. Starting with the gallium FIB, which was originally intended for photomask repair in the semiconductor industry, there are now many different types of FIB that are commercially available. These instruments use a range of ion species and are applied broadly in materials science, physics, chemistry, biology, medicine, and even archaeology. The goal of this roadmap is to provide an overview of FIB instrumentation, theory, techniques, and applications. By viewing FIB developments through the lens of various research communities, we aim to identify future pathways for ion source and instrumentation development, as well as emerging applications and opportunities for improved understanding of the complex interplay of ion–solid interactions. We intend to provide a guide for all scientists in the field that identifies common research interest and will support future fruitful interactions connecting tool development, experiment, and theory. While a comprehensive overview of the field is sought, it is not possible to cover all research related to FIB technologies in detail. We give examples of specific projects within the broader context, referencing original works and previous review articles throughout.

We present a technique for local growth of high-resolution, high-aspect-ratio magnetic tips and thin adherent magnetic cap coatings on top of batch fabricated scanning force microscopy silicon tips. A focused electron beam of a scanning electron microscope is used for decomposition of a directed cobalt carbonyl vapor flux. Exposure parameters determine the tip geometry and tip length. Deposits consist of cubic Co clusters of 2–5 nm in size dispersed in a stabilizing carbonaceous matrix. Magnetic force microscope sensors having magnetic tip apex diameters between 50 and 240 nm were produced. Tracks of magnetic transitions written in recording media of hard disks were used to characterize tip performance.

Codeposition of hydrocarbons is a severe problem during focused electron beam writing of pure metal nanostructures. When using organometallic precursors, a low metal content carbonaceous matrix embedding and separating numerous nanosized metal clusters is formed. In this work, we present a new and easy approach to obtain high purity gold lines: the use of inorganic PF3AuCl as a precursor. Electrical resistivities as low as 22 μΩ cm at 295 K (ten times the bulk Au value) were obtained. This is to our knowledge the best value for focused electron beam deposition obtained from the vapor phase so far. No special care was taken to prevent hydrocarbon contamination. The deposited nanostructure consists of gold grains varying in size and percolation with beam parameters.