Simulation of dust particles in dual-frequency capacitively coupled silane discharges

The behavior of nanoparticles in dual-frequency capacitively coupled silane discharges is investigated by employing a one-dimensional self-consistent fluid model. The numerical simulation tries to trace the formation, charging, growth, and transport of dust particles during the discharge, under the influences of the high- and low-frequency electric sources, as well as the gas pressure. The effects of the presence of the nanoparticles and larger anions on the plasma properties are also discussed, especially, for the bulk potential, electron temperature, and densities of various particles. The calculation results show that the nanoparticle density and charge distribution are mainly influenced by the voltage and frequency of the high-frequency source, while the voltage of the low-frequency source can also exert an effect on the nanoparticle formation, compared with the frequency. As the discharge lasts, the electric potential and electron density keep decreasing, while the electron temperature gets increasing after a sudden drop.

Figure 1

(Color online) The spatiotemporal variation profiles of the electron temperature, with $P=300\text{mTorr}$, $V_l=50\text{V}$, $V_h=25\text{V}$, $f_l=3\text{MHz}$, and $f_h=60\text{MHz}$.

Figure 2

(Color online) The spatiotemporal variation profiles of the electric field, with the settings the same as those in Fig. 1.

Figure 3

(Color online) The spatiotemporal variation profiles of the nanoparticle number density, with the settings the same as those in Fig. 1.

Figure 4

The spatial variation profiles of the positive ion and electron number densities within one LF period, with the settings the same as those in Fig. 1.

Figure 5

The spatial variation profiles of the silyl and silylene number densities within one LF period, with the settings the same as those in Fig. 1.

Figure 6

(a) The average nanoparticle’s charge $Q_d/e$ and (b) number density $n_d$ for different HF voltages $V_h=20$, 25, and 30 V with $V_l=50\text{V}$, $P=300\text{mTorr}$, $f_l=3\text{MHz}$, and $f_h=60\text{MHz}$.

Figure 7

(a) The average nanoparticle’s charge $Q_d/e$ and (b) number density $n_d$ for different LF voltages $V_l=50$, 60, and 80 V with $V_h=30\text{V}$, $P=300\text{mTorr}$, $f_l=3\text{MHz}$, and $f_h=60\text{MHz}$.

Figure 8

(a) The average nanoparticle’s charge $Q_d/e$ and (b) number density $n_d$ for different HF frequencies $f_h=30$, 45, and 60 MHz with $f_l=3\text{MHz}$, $P=300\text{mTorr}$, $V_l=50\text{V}$, and $V_h=30\text{V}$.

Figure 9

(a) The average nanoparticle’s charge $Q_d/e$ and (b) number density $n_d$ for different LF frequencies $f_l=3$, 5, and 10 MHz with $f_h=60\text{MHz}$, $P=300\text{mTorr}$, $V_l=50\text{V}$, and $V_h=30\text{V}$.

Figure 10

(a) The average nanoparticle’s charge $Q_d/e$ and (b) number density $n_d$ for different gas pressures $P=250$, 300, and 350 mTorr with $V_l=50\text{V}$, $V_h=30\text{V}$, $f_l=3\text{MHz}$, and $f_h=60\text{MHz}$.

Figure 11

The temporal variation profiles of the number densities of the particles, as well as the potential and electron temperature, in the center of the discharge, throughout the whole discharge time, approximate 0.4 ms, with $P=300\text{mTorr}$, $V_l=50\text{V}$, $V_h=25\text{V}$, $f_l=3\text{MHz}$, and $f_h=60\text{MHz}$.