engleski

EMISSION OPTICAL SPECTROSCOPY STUDY OF RF OXYGEN PLASMA VERSUS PRESSURE

Optical emission spectroscopy of inductively coupled RF oxygen plasma has been performed in the range of oxygen pressure xx to yx Pa.. Plasma was generated within a glass tube of 36 mm internal diameter with an RF generator with the frequency of 27.12 MHz and the output power of 300 W. Plasma parameters were determined by means of a double electrical probe and a catalytic probe. The flow of oxygen was established in the tube using a mechanical rotary pump. Spectra were measured in the range from 200 nm to 1100 nm by means of a high-resolution optical fiber spectrometer. Observation was done through a quartz window mounted on the arm of the tube perpendicularly to the coil. At high pressures the main spectral features observed were atomic oxygen transitions at 777.2 nm and 844.8 nm, and molecular oxygen band at 762 nm. The atomic emission intensity shows a maximum at about 75 Pa, while molecular band intensity increases monotonic as the total pressure increase. By decreasing oxygen pressure other atomic and molecular features appear in spectra, such as H atomic lines, and molecular OH band etc. The increase of atomic and molecular features follows different paths. The behavior of intensity dependence on pressure is discussed in terms of different discharge modes.

plasma; oxygen; emission spectroscopy; inductively coupled RF discharge

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