Influence of Gas Temperature on Nucleation and Growth of Dust Nanoparticles in RF Plasma

The aim of this work is to study the influence of gas temperature on the nucleation and growth mechanism of nanoparticles in order to deeper understand the growth process of carbonaceous nanoparticles in the plasma of a capacitively coupled radio frequency (RF) discharge. For this purpose, a method based on the time evolution of the self-bias voltage amplitude Vdc was used. The obtained results show that the synthesis (nucleation and growth) time of nanoparticles depends on plasma parameters: RF power and gas temperature. It was found that with an increase in the gas temperature from 25 °C (room temperature) up to 100 °C, the nucleation time increases by four times and with a decrease in the temperature from 25 °C to -20 °C, the nucleation requires half the time. The obtained experimental data and calculations, based on the orbital motion limited theory, give an opportunity to predict the values of nanoparticle diameter and concentration in the plasma-enhanced chemical vapor deposition (PECVD) process in a wide range of gas temperature. These results are important for practical applications of nanoparticle growth control in PECVD processes.