Formation of spherical Sn particles by reducing SnO2 film in floating wire-assisted H2/Ar plasma at atmospheric pressure

Abstract

A green method to synthesize spherical Sn particles by reducing SnO2 film in atmospheric-pressure H2/Ar plasma at low temperatures for various applications is presented. The floating wire-assisted remotely-generated plasma with a mixture of 0.05% H2/Ar gas formed spherical metallic Sn particles by reducing a SnO2 layer on glass substrate. During the reduction process, H radical density was measured by using vacuum ultraviolet absorption spectroscopy, and plasma properties including electron density and gas temperature were diagnosed by optical emission spectroscopy. The inductively coupled generated plasma with a high electron density of 1014 cm−3, a hydrogen atom density of 1014 cm−3, and a gas temperature of 940 K was obtained at a remote region distance of 150 mm where the SnO2/glass substrate was placed for plasma treatment. The process has been modeled on the spherical Sn formation based on the reduction of SnO2 films using H radicals. Depending on the treatment condition, the total reduction area, where spherical Sn particles formed, was enlarged and could reach 300 mm2 after 2 min. The substrate temperature affected the expansion rate of the total reduction area and the growth of the Sn spheres.

Low‐temperature reduction of SnO2by floating wire‐assisted medium‐pressure H2/Ar plasma

“…The electron densities of medium-pressure H 2 /Ar plasma generated was 2.04 × 10 14 cm −3 at 10 kPa. The electron density at 10 kPa is still in the order of 10 14 cm −3 , resulting in producing a rich H radical source with 3.4 × 10 14 cm −3 as estimated from our previous study, [15] as reported that the absolute H radical density at 150 W was 7 × 10 14 cm −3 at 70 kPa. The percentage of H 2 gas in the H 2 /Ar gas mixture is only 0.05%.…”

“…[11] In contrast to the abovementioned thermal reduction processes, plasma shows advantages in controlling the reaction process. [11][12][13][14][15] Among plasma techniques, using atmospheric pressure (AP) plasma to reduce metal oxides to metals has not been intensively studied. [16][17][18] Although vacuum plasma is able to be well controlled over gas chemistry and produces high energetic species in processes of surface modification, [19,20] AP plasma is able to miniaturize equipment size, reduce fabrication cost, and lower energy consumption.…”

“…[21][22][23] In our previous study, in the use of the AP process, the reduction of SnO 2 film was developed by using floating wire-assisted (FW)-H 2 /Ar plasma that can generate a rich H radical source (10 14 cm −3 ). [15] By using the FW electrode, high-density and large-volume plasma can be produced at a remote region. [21][22][23] Between vacuum and AP plasma technologies, medium-pressure plasma (widepressure range: 0.2-50 kPa) can achieve larger-volume plasma compared to AP plasma and minimized pumping equipment compared to low-pressure plasma.…”

“…The effect of substrate temperature (T sub ) was discussed in our previous paper. [15] When SnO 2 was reduced to Sn, recombination of H radicals on the spherical Sn particle surface produces heat as the reaction (3), [35,36] which accelerates the reaction (2) for etching Sn.…”

OpenDust: A fast GPU-accelerated code for calculation forces, acting on microparticles in a plasma flow

“…Problem of calculation forces, acting on microparticles of condensed matter, so-called dust particles, in a plasma flowing environment, arises in a variety of industry applications [1,2,3] and fundamental issues [4,5,6,7], related to the complex plasma physics [8]. For example, flowing plasma can lead to the release of pollutant particles from a processed sample during extreme ultraviolet lithography important for microelectronics [1,3,2], which can lower the quality and productivity of the manufacturing processes. Controlling and minimizing contamination of such particles requires detailed study of the forces, acting on them.…”