Exotic phenomena in plasmas at extremely low pressure

摘要

With increasing demands on technological applications of plasmas, in particular from plasma etching, high aspect ratios and large area uniformity are desired. This motivates the magnetic neutral loop discharge (NLD). This plasma concept utilises an inhomogeneous static magnetic field configuration, with a neutral loop (NL) region where the magnetic field vanishes. An inductive rf electric field is superimposed on this NL. Due to electron confinement and efficient collisionless electron heating, the NLD allows operation at pressures, down to 10~(-2) Pa. Interesting phenomena arise and a combination of various diagnostics is essential for detailed insight: Langmuir probe, phase resolved optical emission spectroscopy (PROES), Thomson scattering, laser absorption spectroscopy, and laser induced fluorescence on neutral particles are employed.