Plasma Chemical Study of a RF Discharge Containing Aluminum Tri‐Isopropoxide Using MIR Absorption Spectroscopy Based on External‐Cavity Quantum Cascade Lasers

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International audienceIn Ar and Ar/N2 radio frequency (RF) discharges with admixtures of aluminium tri-isopropoxide (ATI) the fragmentation of this metal-organic precursor was studied by means of Fourier Transform Infrared (FTIR) spectroscopy using an optical long path cell providing an optical length of l= 17.2 m. The experiments were performed in an asymmetric capacitively coupled process plasma at a frequency of f= 13.56 MHz and at pressure values in the range of p= 1 - 10.5 Pa. The discharge power was chosen between P= 10 - 100 W. Using FTIR spectroscopy the evolution of the concentrations of ATI and of six stable molecules, CH4, C2H2, C2H4, C2H6, CO and HCN, was monitored under flowing conditions at gas flows of Φtotal= 0.5 - 14.5 sccm in the discharge. The concentrations of the reaction products were measured to be between 2 x 1012 molecules cm−3 as e.g. found for C2H4 and C2H6, and 5 x 1013 molecules cm−3, as e.g. in the case of CO. In the plasma a complete dissociation of the precursor ATI was found at a power value of about P= 80 W independent on the admixture of Ar or N2. The fragmentation efficiency (FE) of the reaction products which originate from the ATI molecules ranges between 0.2 and 4 x 1016 molecules J−1 while the fragmentation rate (FR) reached up to 2.5 x 1018 molecules s−1. The multi component detection ability of the spectrometer served to analyse the carbon balance of the by-product formation. For all experiments, the carbon balance never exceeded 25%. Therefore, in the plasmas the majority of the provided carbon is most likely deposited at the reactor walls or forms dust particles or higher molecular CxHy. The conversion efficiencies (CE) of the produced molecular species ranges between 0.1 x 1015 molecules J−1 for C2H4 and 5 x 1015 molecules J−1 for C2H6 depending on the discharge conditions of the RF plasma

Section: Methodsmentioning

confidence: 99%

Section: Ati Behaviour As a Function Of The Mixing Ratio Experimentsmentioning

confidence: 99%

Section: By-product Formation As a Function Of The Mixing Ratio Expementioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

“…The results of the recent QCLAS study suffered from a limited spectral range, which could only be analysed. In particular, the precursor ATI itself could not be monitored [17].…”

Section: Introductionmentioning

confidence: 99%

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On the Plasma Chemistry of an RF Discharge Containing Aluminium Tri‐Isopropoxide Studied by FTIR Spectroscopy

Hübner¹,

Fröhlich²,

Tawidian³

et al. 2014

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Study of thin Film Formation From Silicon‐Containing Precursors Produced by an RF Non‐Thermal Plasma Jet at Atmospheric Pressure

Schäfer

Foest

Sigeneger

et al. 2012

The deposition of thin silicon-organic films by atmospheric pressure PECVD using an RF-excited plasma jet has been investigated experimentally and theoretically. Static deposition experiments have been performed on flat polymer and glass samples using the silicon containing molecules HMDSO, OMCTS and silane. The experiments are classified with respect to power, flow rate, operating conditions and deposition rate. The deposited films have been analysed using profilometry and Fourier transform infrared spectroscopy. It is found that electric power and gas flow stability determine distinctive areas in the operating diagram characterized by the deposition rate, profile shape and the chemical properties of the film depending on introduced precursors. The highest O/Si ratio (close to two) is found for laminar flow regimes. Here, the films are characterized by a low carbon content, too. The experimental findings for different flow conditions are discussed in relation to results of a two-dimensional axisymmetric fluid model. The model predicts the interaction of gas heating and flow, the plasma generation in the active volume, the transport of active plasma particles into the effluent and the generation and transport of precursor fragments towards the substrate surface. A remarkable influence of the gas flow on the plasma kinetics is observed only with respect to the density of molecular argon ions, which are transported together with electrons into the effluent. The calculated flux of precursor fragments onto the substrate surface agrees qualitatively with measured profiles of the film thickness.

Recent Progress in Complex Plasmas

Meichsner

Bönitz

Piel

et al. 2012

An overview on recent developments in the field of complex plasmas is presented. The focus is directed on the activities of research groups participating in the Collaborative Research Centre 24 “Fundamentals of Complex Plasmas” at the Universities in Greifswald and Kiel as well as at the Leibniz‐Institute for Plasma Research and Technology. This article summarizes results on strongly correlated dusty plasmas, reactive as well as electronegative plasmas and plasma‐surface interaction, and gives an introduction to the following articles of this special issue. Important developments are highlighted and future research directions are outlined (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)