Focused Electron Beam Induced Processing (FEBIP) enables direct-write nanoscale fabrication with a variety of materials. Compared to a similar technique – focused ion beam deposition – FEBIP can achieve much higher resolution, inflicts less surface damage, and involves more accessible tools. However, FEBIP is not widely used due to its limited deposition rate, low material purity, and limitation on a type of precursor materials, which can be delivered to a high vacuum environment of the FEBIP chamber. We are developing a family of multi-mode energized micro/nano-jet techniques as a method of local precursor delivery, which aiming to resolve both issues and to expand the range of useful precursors for applications in FEBIP. In this presentation, we will discuss the fundamentals of several new methods, including electrospray nano-jets and supersonic gas micro-jets, we have developed for delivery of energized precursor molecules into a vacuum environment of the FEBIP chamber. The results of experimental characterization of the jet behavior upon impact on the substrate will be presented with implications to FEBIP deposit growth rate, topology and purity.
Energized micro/nano-jets provide unique capabilities for localized delivery of precursor molecules to the substrate, thus establishing locally controlled deposition/etching/doping site for focused electron-beam induced processing (FEBIP). Not only this enables FEBIP from precursor materials of different kinds, but also affords tuning of sticking coefficients and adsorption/desorption activation energies of participating molecules. The latter is especially critical for substrates, which are sensitive to doping such as graphene, whose electronic properties change by adsorption of different molecules. This avenue for future FEBIP development is most promising from the application prospective, as an emerging multi-functional (electron/photon/molecule beam) FEBID/FEBIE operation establishes an intimately integrated multi-functional processing environment that enables one to define shapes (patterning), form structures (deposition/etching), and modify (cleaning/doping/annealing) properties with locally-resolved control on nanoscale within the same tool without ever changing the processing environment. This, in turn, should allow for (1) increasing the process throughput by minimization of a number of intermediate “handling steps” (which is a deficiency for all beam based techniques as compared to batch fabrication), (2) the possibility to create almost an arbitrarily diverse portfolio of different device structures/functionalities on the same substrate due to “direct-write” nature of the approach, and (3) the capability for local property control/modification while minimizing the parasitic substrate contamination in the course of processing, which is especially critical for graphene-like electronic materials, whose properties are highly sensitive to intended or unintended dopants.