Studies on sheath and related phenomena in post magnetron and double plasma device

Abstract

The aim of the present thesis is to investigate the basic physics of some de discharge plasmas related to the material processing applications. In this thesis we are reporting the results of: (a) study of the properties of post magnetron discharge plasma. sheath formation and related instabilities in such a discharge, (b) behaviour of ion sheath under the influence of low energy ion beam investigated in a double plasma device, (c) plasma properties and sheath characteristics under the influence of low energy electron beam. Post magnetron is a plasma device mainly used for sputtering in a cylindrical geometry in this system an axial magnetic field is created parallel to the cathode surface and perpendicular to the applied electric field. Due to the action of EXB field, the electrons follow a cycloidal path around the cathode. As a result electron lifetime and path length around the cathode increases. Due to this, electron-neutral collision probability and hence the ionization rate increases. So plasma density increases in such a system due to higher confinement and higher rate of ionization. In the Chapter-1, an introduction to the post magnetron discharge and plasma sheath is given along with the related literature. A post magnetron plasma system has been designed and installed for the study of basic physics of magnetron discharge plasma. A high voltage de discharge power supply (1000 v/ 1 Amp) has been indigenously fabricated and successfully used for discharge. A detailed description of the experimental system is given in chapter - 2. The diagnostics used for the investigation such as Langmuir probe, Emissive probe and Retarding potential analyzer and related instrumentation are also described in this chapter. Chapter-3 represents the experimental investigation on the plasma properties. sheath and related instability in a post magnetron device. Discharge current-voltage characteristics of a direct current post magnetron plasma system have been studied at different discharge conditions. With increasing the...