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P: Plasmaphysik

P 7: Poster: Niedertemperaturplasmen / Plasmatechnologie 3, Diagnostik 3

P 7.6: Poster

Freitag, 4. März 2005, 16:30–18:30, Poster HU

Time resolved measurements of transient and stable fluorocarbon species in pulsed rf discharges using IR Tuneable Diode Laser Absorption Spectroscopy (IR-TDLAS) — •Onno Gabriel, Serguei Stepanov, Konstantin Li und Jürgen Meichsner — Institut für Physik, Domstraße 10a, 17489 Greifswald

The concentrations of small radicals and stable molecules in fluorocarbon rf plasmas are investigated by time resolved IR-TDLAS. The TDLAS system (single path arrangement) is adapted to a rf plasma apparatus consisting of a vacuum chamber of 20 l equipped with asymmetric, capacitively coupled rf discharge, and in situ ellipsometer for measuring the film thickness of fluorocarbon films on the rf electrode simultaneously. Typical processing parameters are rf power (cw) 10–100 W, gas flow of 1–20 sccm, and total pressure of 10–100 Pa. The rf discharge at 13.56 MHz is driven in pulsed mode with frequencies of between 0.1 to 100 Hz, and at various duty cycles. By use of the processing gases CF₄, H₂, and C₂F₆ the analysis of small transient species (CF, CF₂, CF₃) and stable products (C₂F₄) are in the focus of investigations. In particular, the role such species in the deposition and/or etching processes of fluorocarbon layers are of special interest. The applied TDLAS provides line integrated absolute molecule concentrations with time resolutions down to 50 µs. From generation and decay curves of several transient and stable species in pulsed plasmas information are obtained about characteristic reaction times, rate coefficients, and dominant reaction channels.