Nanopowder management and control of plasma parameters in electronegative SiH4 plasmas

Abstract

Femtosecond laser guiding of a high-voltage discharge and the restoration of dielectric strength in air and nitrogen Phys. Plasmas 19, 123502 (2012) Compact high-speed reciprocating probe system for measurements in a Hall thruster discharge and plume Rev. Sci. Instrum. 83, 123503 (2012) On the streamer propagation in methane plasma discharges J. Appl. Phys. 112, 113301 (2012) One-dimensional hybrid-direct kinetic simulation of the discharge plasma in a Hall thruster Phys. Plasmas 19, 113508 (2012) Consideration of the electron energy distribution function shape in a Ar and N2 global model J. Appl. Phys. 112, 103303 (2012) Additional information on J. Appl. Phys. Management of nanosize powder particles via control of plasma parameters in a low-pressure SiH 4 discharge for silicon microfabrication technologies is considered. The spatial profiles of electron and positive/negative ion number densities, electron temperature, and charge of the fine particles are obtained using a self-consistent fluid model of the electronegative plasmas in the parallel plate reactor geometry. The model accounts for variable powder size and number density, powder-charge distribution, local plasma nonuniformity, as well as UV photodetachment of electrons from the nanoparticles. The relations between the equilibrium discharge state and powder properties and the input power and neutral gas pressure are studied. Methods for controlling the electron temperature and SiH 3 Ϫ anion ͑here assumed to be the powder precursor͒ density, and hence the powder growth process, are proposed. It is shown that by controlling the neutral gas pressure, input power, and powder size and density, plasma density profiles with high levels of uniformity can be achieved. Management of powder charge distribution is also possible through control of the external parameters.

Single-step, rapid low-temperature synthesis of Si quantum dots embedded in an amorphous SiC matrix in high-density reactive plasmas

“…This gives rise to a large amount of hydrogen atoms in the plasmas because of the high-dissociation degree of the silane and methane molecules even without any hydrogen dilution of the reactant gases in the ICPbased process [17][18][19]. Under such conditions, a large surface coverage by hydrogen atoms can be achieved, which enables the adsorbed Si-based radicals to reach the most energetically favorable sites [4,17,40].…”

“…Recently, Si quantum dots (QDs) embedded in a dielectric matrix have attracted a great deal of interest and have been a subject of intense scientific activities, owing to their immensely promising applications in the third generation photovoltaic solar cells [1][2][3][4][5]. The third-generation all-Si tandem photovoltaic solar cells, which rely on the quantum confinement effects in the embedded Si quantum dots, are expected to overcome the Shockley-Queisser limit of conventional solar cells and reach the high-energy conversion efficiency of 47.5% using three-cell tandem stacks [6,7].…”

Inductively coupled plasma-assisted RF magnetron sputtering deposition of boron-doped microcrystalline Si films

“…Compared to B-doped amorphous Si, this material has a higher dark conductivity, carrier mobility, doping efficiency, optical transparency, etc., due to the presence of Si crystallites embedded in the amorphous Si or Si-based matrices [8][9][10][11][12][13][14].…”

Nonlinear structures of strongly coupled complex plasmas in the proximity of a presheath/sheath edge

“…In this paper, however, we address the situation when the gravitational force acting on the particles is negligible, the particles are strongly coupled and the dust cloud extends over the discharge plasma occupying the volume up to a boundary presheath/sheath. These conditions could be relevant for studies of complex plasmas under microgravity conditions (see, e.g., [15]- [18]), for thermophoretically levitated systems [19], for experiments on nanoparticle coagulation [20] and for processing plasmas dealing also with very small (submicron/nanometer-sized) particles [21,22].…”