Templated i‐PVD of Metallic Nanodot Arrays

Abstract

The results of numerical simulation of plasma‐based, porous, template‐assisted nanofabrication of Au nanodot arrays on highly‐doped silicon taking into account typical electron density of low‐temperature plasma of 1017–1018 m−3 and electron temperature of 2–5 eV are reported here. Three‐dimensional microscopic topography of ion flux distribution over the outer and inner surfaces of the nanoporous template is obtained via numerical simulation of Au ion trajectories in the plasma sheath, in the close proximity of, and inside the nanopores. It is shown that, by manipulating the electron temperature, the cross‐sheath potential drop, and by additionally altering the structure of the nanoporous template, one can control the ion fluxes within the nanopores, and eventually maximize the ion deposition onto the top surface of the developing crystalline Au nanodots (see top panel in the figure). In the same time, this procedure allows one to minimize amorphous deposits on the sidewalls that clutter and may eventually close the nanopores, thus disrupting the nanodot growth process, as it is shown in the bottom panel in the figure on the right.

Plasmas meet plasmonics

“…This in turn affects the way particles self-organise into a nano-array. Whilst the most popular methods to form nanostructures for plasmonics are currently e-beam and nanosphere lithography and nanotemplating, plasmas are a useful alternative that can be used to control the deposition of metals or metal oxides through nanoporous templates to create size uniform, regular arrays [125,126], as well as in conjunction with nanosphere lithography [127]. This control over the generation of nanostructure material, transport to and interaction with the surface is enabled by careful modification of the plasma parameters such as power, pressure, gas composition, etc.…”

“…Methods to construct nanostructure arrays suitable for this purpose include fragmentation after thermal evaporation [179], as well as plasma-assisted nanosphere lithography [127] and plasma-assisted deposition through nanopore arrays [125,126] discussed in Section 4.2. The benefit there is that the size of the nanoparticles in template-based methods is more controllable than in stress-induced fragmentation [186] which results in a very broad island size distribution.…”

Nanopore processing in dielectric materials and dielectric template-assisted nanoarray synthesis: Using pulsed bias to enhance process throughput and precision

“…17 Using ionized gas environments, such as plasma discharges and ion/charged nanocluster beams, has a number of significant advantages such as better and highly controlled species penetration and interaction with the surfaces of nanopores and underlying substrates. 18 However, electric charge accumulated on dielectric surfaces exposed to plasmas and ion beams distorts ion/cluster trajectories and reduces the process throughput and precision. 19 This is why attempts have been made to periodically remove the accumulated charge by applying ac or pulsed voltages to bias the dielectric materials being processed, sustain the plasma, or release suitable building units.…”

“…The ion motion until collision with the TSS surfaces is described using the electric field distribution in the sheath and in the vicinity of the TSS taking into account the distribution of the electrostatic potential within the plasma sheath and its distortion near the pore openings. 16,18 The numerical experiment performed for each set of parameters involved 300 000 ions traced one after another until collision with the TSS surface. The initial position of each ion at the sheath boundary z = was chosen randomly, and their velocity at the boundary was assumed to be equal to the Bohm velocity v B = ͑T e / m i ͒ 1/2 , where m i is the ion mass.…”

Contribution of radicals and ions in catalyzed growth of single-walled carbon nanotubes from low-temperature plasmas

“…[14][15][16][17][18][19][20][21][22][23][24] The significant recent interest in reactive plasmas for materials processing is due to their numerous remarkable characteristics. [25][26][27][28][29] Through the various plasma-chemical reactions, occurring in the gas phase of the plasma, diverse combinations of electrons, ions, and radicals are created. The ions accelerated by the plasma sheath electric field at the plasma-substrate interface accompanied with fluxes of highly reactive radicals towards the substrate provide the required carbon-bearing species for the plasma-based synthesis of high-aspect-ratio carbon nanostructures.…”