Focused Ion Beam Parameters for the Preparation of Oxidic Ceramic Materials

Abstract

The focused ion beam (FIB) technology is a useful tool for structuring and preparing material surfaces on a micrometer and nanometer scale. [1,2] The technology is based on the principle that ions are extracted from an ion source (e.g., a liquid metal ion source, most commonly Ga þ , or gas field ion sources, such as He þ ) by an electric field. [1] Then, they are accelerated toward the substrate surface and focused to form an ion beam by applied electric and magnetic fields. For Ga þ sources, typical acceleration voltages are 5-50 keV and a beam focus <10 nm can be realized. The ion current is usually in the range of tenths of picoamperes to several nanoamperes. [2,3] When the focused ion beam meets the surface of the target material, various interactions between the incident ion beam and target surface occur. [1] First, the incident ions of the beam enter the sample. Due to interactions with the target atoms (nuclei and electrons), the ions are deflected. Second, collisions with target atoms are likely to take place. This may cause a removal of a target atom from its lattice position. Then, the removed target atom can collide with further target atoms, creating collision cascades. Numerous cascades will reach the sample surface, and if provided sufficient energy, will remove atoms from the sample surface. This effect is called sputtering. These processes of ions penetrating and leaving the sample surface are accompanied by the ejection of secondary electrons from the sample surface. Numerous ions that penetrate the surface remain as implanted ions in the target material.These interactions between the FIB and the material surfaces can be brought to several uses for the industrial operator or scientists. 1) Imaging: The ejected secondary electrons and ions from the surface can be used for imaging purposes. [1] 2) Sputtering: This removal of material from the target surface, also called milling, can be used to produce defined samples for further analytical applications (e.g., production of lamellar samples for transmission electron microscopy (TEM) [4,5] ), to structure material surfaces down to the nanometer scale (e.g., structuring of semiconductors [3,6] or samples for mechanical testing on a micrometer scale [7,8] ), and to create serial sections by repeated milling steps for 3D analyses of bulk material. [9] Furthermore, the removed material can be used for elemental analysis of the material surface with the help of secondary ion mass spectrometry (SIMS). [2] 3) Creation of structures: The energy provided by the incident ions can be used to deposit other elements that are provided by precursor molecules. They are introduced via a gas injection system (GIS) on the substrate surface. Due to the energetic input of the ion beam, cracking reactions take place in the precursors and the intended component of the precursor molecules is deposited on the material (e.g., deposition of electrically conductive metallic

Ion‐Implantation in Titania‐Based Plasmonic Photo‐anodes: A Review

“…[69,73] In the current times, ion beam technology has been demonstrated to be a potential method for material modification. [60,61,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90] This method has substituted the diffusion [5,74,[91][92][93] process when compared to the conventional doing strategies and has been widely used in the synthesis of nanomaterials [74,75,84,86,89,91] for photo-catalysis, [5,6,28,94,95] photo-electrochemical water-splitting, [3,36,96,97] and photo-voltaic [35,[98][99][100] applications. Significant advances have been made in the synthesis of plasmonic nanocomposites by this method in the last couple of years.…”