Time‐resolved analysis of the precursor fragmentation kinetics in an hybrid PVD/PECVD dusty plasma with pulsed injection of HMDSO

Abstract

Plasma sampling mass spectrometry (PSMS) has been carried out to study the fragmentation kinetics of hexamethyldisiloxane (HMDSO) in a low-pressure, axially asymmetric argon rf discharge designed for the growth of nanocomposite thin films through a hybrid PVD/PECVD method. Experiments have been conducted with a pulsed injection of HMDSO over a 5-s period. Plasma conditions have been chosen to favor formation and disappearance of dust occurring in cycles of a few hundred seconds. The dissociation degree of HMDSO and the relative intensities of HMDSO-related fragments are reported and analyzed regarding these two specific time-scales. PSMS showed that formation of dust increases HMDSO dissociation. The same result can be deduced from the particle balance equation of HMDSO using the electron density and temperature obtained from optical emission spectroscopy as the only input parameters. For HMDSO, electron-impact dissociation is the dominant loss pathway over diffusion and recombination on the reactor walls. Small C x H y compounds and H 2 are mostly generated from surface recombination mechanisms and lost by electron-impact dissociation. K E Y W O R D S organosilicon precursors, physical vapor deposition, plasma diagnostics, plasma-enhanced chemical vapor deposition 2 of 12 | GAROFANO ET AL. F I G U R E 7 Temporal variation of the fragment-to-parent molecule PSMS ratios (m/z 2-133 / m/z 147) during the formation and disappearance of the dust cloud. Standard conditions. PSMS, plasma sampling mass spectrometry GAROFANO ET AL.

Discharge dynamics, plasma kinetics and gas flow effect in argon–acetylene discharges

“…With regard to the radicals, it is well known that the recombination coefficient greatly depends on the processing conditions such as temperature or surface composition [33], [59], [16]. Such variations could greatly impact the deposition process but have limited influence on the discharge dynamics as shown in [60]. Therefore, we have adopted constant values of sticking coefficients.…”

Simulation study of organosilicon coating of a spherical nanoparticle immersed in a low-pressure HMDSO/O2 plasma

“…The elevation of the processing pressure tends to enhance the film deposition rate [25]. Also, the increase in pressure can reduce the dissociation rate of HMDSO molecules, which may result in the formation of dust nanoparticles in the plasma phase [32][33][34][35][36].…”

Direct Liquid Reactor-Injector of Nanoparticles: A Safer-by-Design Aerosol Injection for Nanocomposite Thin-Film Deposition Adapted to Various Plasma-Assisted Processes

“…The charging of droplets in plasmas also promotes their electrical confinement enhancing their residence time in the plasma volume [29]. Consequently, plasmadroplet interactions can have a significant effect, not only on the plasma behavior (e.g., electron temperatures, plasma densities, and transport properties [30][31][32][33]), but also on the plasmadeposition process (e.g., precursor fragmentation [34], thin-film deposition rates [18,35], and degree of plasma polymerization [36,37]).…”