Laser light scattering from silicon particles generated in an argon diluted silane plasma

Abstract

We conducted laser light scattering (LLS) measurements in a 13.56 MHz capacitively coupled dusty plasma maintained in silane and argon to study the spatial distribution of silicon nanoparticles and nanoparticle agglomerates. Specifically, we focused on the temporal evolution of their spatial distribution in the plasma as a function of pressure and power. We observed three distinct types of temporal evolution behavior of the nanoparticle dust cloud in the plasma and classified these into three regimes based on pressure and power. Each regime features a distinct pattern in laser light scattering measurements. At low pressures (∼80-100 mTorr) and high powers (∼40-60 W) we observed periodically repeating expansions and contractions of a continuous dust cloud for the first time. Dust voids, which have been reported before, were also observed at high pressures (∼100-150 mTorr) and low powers (∼20-40 W) in the center of the plasma. A mechanism is proposed to explain the observed dynamics of the nanoparticles. The balance between the ion drag force and electrostatic forces and their dependence on particle size are hypothesized to be the dominant factors that determine the nanoparticle cloud dynamics.

In-Flight Size Focusing of Aerosols by a Low Temperature Plasma

“…Of course, the other option is that particle heating may be the more important vaporization process. The mismatch between model and experiment in the time scales of condensation is possibly due to higher local vapor concentrations because of vapor ionization and particle confinement effects. , Future work will focus on including these phenomena and deconvolution of the vaporization mechanisms.…”

Temporal dusty plasma afterglow: A review

“…Due to their mass, injected particles are usually confined near the electrode where the electric force can balance the gravity force unless the experiment is performed under microgravity [13][14][15] or a thermophoresis force is applied [16,17] to create a dust cloud filling the bulk plasma. Dense clouds of submicron particles light enough to stay in the bulk plasma can be obtained using reactive gases such as silane [18][19][20] and acetylene [21][22][23] or using a target sputtered with ions coming from the plasma [24][25][26]. In complex plasmas, the electric charge of the grains is obviously a key parameter.…”

In Situ Laser Light Scattering for Temporally and Locally Resolved Studies on Nanoparticle Trapping in a Gas Aggregation Source

“…Some methods rely on Mie scattering [39][40][41] and others on Rayleigh scattering. [42][43][44][45] Mie scattering techniques are Mie ellipsometry, angular-resolved Mie scattering, and 2D imaging Mie ellipsometry. By these methods, NPs of radii between 80-200 nm can be detected, for example, inside a dusty plasma.…”

“…In this way the LLS technique was often used in conventional RF dusty plasmas but not in a GAS. [42][43][44][45] Here no information about the size distributions can be found, but other techniques like in situ SAX or in situ UV-Vis can provide this information. However, they cannot provide precise information about the location of NPs.…”