Optimised Plasma Absorption Probe for the Electron Density Determination in Reactive Plasmas

Abstract

The plasma absorption probe (PAP) is a recently developed tool for the efficient determination of electron densities, especially in reactive plasmas. A dielectric cover protects this probe against the influences in reactive plasmas and it withstands conditions where Langmuir probes are easily damageable. The lack of adequate calibration constants and the occurrence of multiple absorption signals were two major drawbacks, which are successfully overcome in this work. Design variations are tested by numerical computation and the model‐based achievements are established in experiment. In this work, a redesigned PAP is presented, which is optimised for the easy determination of electron densities. The developed tool works fast and efficiently, in particular in discharges in reactive gases.

The Role of Argon Metastables in an Inductively Coupled Plasma for Treatment of PET

“…Electron densities (stars) were also measured 2 cm above the grounded electrode using a PAP as described, e.g., by Scharwitz et al or Lapke et al Similar to Ar m densities, n e drops nonlinearly with increasing admixture of C 2 H 2 from 1.9 × 10 11 cm −3 in pure argon to 0.2 × 10 11 cm −3 at 95% C 2 H 2 gas flow. The expected decrease of the electron density already at small admixtures of C 2 H 2 is not observed, probably because two effects counteract under these conditions: the change in the EEDF as compared to the pure argon case, tending to decrease n e , and the small ionization energy of C 2 H 2 and its decomposition products, tending to increase n e .…”

“…We compare this with ion fluxes to the surface determined via the quasi‐neutrality argument from Langmuir‐probe investigations of the electron energy distribution function (EEDF). The electron density is measured by plasma absorption probe (PAP) . We determine these quantities for a reactor, which is used for barrier film deposition on PET.…”

Adhesion of Thin CVD Films on Pulsed Plasma Pre-Treated Polypropylene

“…During the pre‐treatment processes, the chamber pressure is kept at 5 Pa. Electron densities during the plasma on‐time of about 1 × 10 17 m −3 for oxygen treatments and 6 × 10 16 m −3 for argon at 10 mm distance from the sample is attained by adjusting the power input. The electron densities are determined with a plasma absorption probe (PAP), which was described in detail elsewhere …”

Deposition of SiOx coatings by inductively coupled plasma: Effect of pulsed hexamethyldisiloxan flow

“…The plasma absorption probe (PAP) is a diagnostic tool developed by H. Sugai in 1999 and was improved afterwards . It is used to obtain values for the electron densities in reactive plasmas.…”