Gas-assisted focused electron beam and ion beam processing and fabrication

Abstract

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 ͑milling͒, 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.

Nanopillar growth by focused helium ion-beam-induced deposition

“…The vertical growth rate increases with increasing beam current, but it levels off at the higher currents ( figure 5(b)). This behaviour is unmistakably characteristic for the transition from an ion-limited growth regime to a precursor-limited regime [9]. The vertical growth rate v V can be described by [9,34,35] …”

Controlled Evaluation of Silver Nanoparticle Dissolution Using Atomic Force Microscopy

“…86 Electron-and ion-beam lithography offer high resolution control of features, but these methods are also low-throughput and expensive. [86][87][88] Photolithography is a highthroughput and relatively inexpensive method that allows the controlled fabrication of patterned structures, but objects that are created by photolithography can be no smaller than the diffraction limit of the optical device used during the exposure step. 89 Efforts to overcome this restraint include reaching further into the ultraviolet light range or using X-ray lithography.…”

Importance of Time Scale and Local Environment in Electron-Driven Proton Transfer. The Anion of Acetoacetic Acid

“…5 Finally, fabrication of micro-and nanoelectromechanical devices through electron beam lithography hinges on fundamental electron-driven processes. 6 A special subcategory of proton-coupled electron transfer is excess electron-induced proton transfer. 3,7 Although gas-phase studies of excess electron-induced proton transfer in DNA and proteins are challenging because of the low vapor pressures of these molecules, 3,8 this difficulty has been significantly reduced in the cases of subunits of DNA, e.g., base pairs, nucleosides, and nucleotides, by the development of specialized, laser desorption/photoemission anion sources for bringing them into the gas phase as intact anions.…”