Direct measurements of the energy flux due to chemical reactions at the surface of a silicon sample interacting with a SF6 plasma

TL;DR

This study directly measures the energy flux caused by chemical reactions at a silicon surface interacting with SF6 plasma, revealing significant energy contributions and providing insights into reaction enthalpy.

Contribution

It introduces a method to directly quantify energy flux from chemical reactions at a plasma-surface interface using a heat flux microsensor.

Findings

Chemical reactions contribute about 7 W/cm² to energy flux at 800 W plasma power.

The measured molar enthalpy of SiF4 formation aligns with literature values.

Time evolution of energy flux reveals reaction dynamics over time.

Abstract

Energy exchanges due to chemical reactions between a silicon surface and a SF6 plasma were directly measured using a heat flux microsensor (HFM). The energy flux evolution was compared with those obtained when only few reactions occur at the surface to show the part of chemical reactions. At 800 W, the measured energy flux due to chemical reactions is estimated at about 7 W.cm\^{-2} against 0.4 W.cm\^{-2} for ion bombardment and other contributions. Time evolution of the HFM signal is also studied. The molar enthalpy of the reaction giving SiF4 molecules was evaluated and is consistent with values given in literature.