Electron-beam-induced deposition and post-treatment processes to locally generate clean titanium oxide nanostructures on Si(100)

Abstract

We have investigated the lithographic generation of TiO(x) nanostructures on Si(100) via electron-beam-induced deposition (EBID) of titanium tetraisopropoxide (TTIP) in ultra-high vacuum (UHV) by scanning electron microscopy (SEM) and local Auger electron spectroscopy (AES). In addition, the fabricated nanostructures were also characterized ex situ via atomic force microscopy (AFM) under ambient conditions. In EBID, a highly focused electron beam is used to locally decompose precursor molecules and thereby to generate a deposit. A drawback of this nanofabrication technique is the unintended deposition of material in the vicinity of the impact position of the primary electron beam due to so-called proximity effects. Herein, we present a post-treatment procedure to deplete the unintended deposits by moderate sputtering after the deposition process. Moreover, we were able to observe the formation of pure titanium oxide nanocrystals (<100 nm) in situ upon heating the sample in a well-defined oxygen atmosphere. While the nanocrystal growth for the as-deposited structures also occurs in the surroundings of the irradiated area due to proximity effects, it is limited to the pre-defined regions, if the sample was sputtered before heating the sample under oxygen atmosphere. The described two-step post-treatment procedure after EBID presents a new pathway for the fabrication of clean localized nanostructures.

Focused electron beam induced deposition: A perspective

“…From this perspective FEBID will have to move towards a better microscopic understanding of all relevant processes in a controlled environment, i.e., under UHV conditions and augmented by a selection of surface science analysis techniques. One may hope that results from research under these much better controlled conditions (see e.g., [65–66]) will also be helpful to optimize FEBID processes in the standard SEM environment where it is already today a most attractive technique for structure formation on the nanometer scale.…”

Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structures

“…Hoffmann et al demonstrated the fabrication of high refractive index materials for photonic bandgap structures [13] and Mitchell and Hu reported on the generation of μm-scaled, titanium and oxygencontaining area deposits on gallium arsenide [14,15]. In a previous study we found that with TTIP, even when applied under UHV conditions, the deposits contained significant amounts of carbon, besides the targeted materials titanium and oxygen [16]. The carbon contamination was traced back to the carbon-containing precursor itself.…”

Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

“…FEBID is a versatile technique for nanoprototyping and research, as it permits the deposition of material in a variety of shapes with high spatial resolution. Moreover, it is also possible to deposit oxides [ 10 ] and, by co-injecting different precursors, alloy materials with tunable properties [ 11 ]. A review of the application of the technique to the deposition of magnetic nanostructures has recently been published [ 12 ].…”