AVS 47th International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThM

Paper PS2-ThM7
Energy and Angular Distribution of Ions Effusing from a Hole in Contact with a High Density Plasma

Thursday, October 5, 2000, 10:20 am, Room 311

Session: Plasma Diagnostics II
Presenter: D. Kim, University of Houston
Authors: D. Kim, University of Houston
C.-K. Kim, University of Houston
D.J. Economou, University of Houston
Correspondent: Click to Email
The energy and angular distribution of ions extracted from a hole in contact with a low- temperature plasma have been investigated both computationally and experimentally. A single hole is thought to be a well-defined system for understanding the interaction of a plasma with a biased grid. Such plasma-grid interaction finds applications in neutral beam etching, ion sources, satellite thrusters, etc. The plasma parameters (Debye length), hole diameter and thickness determine the characteristics of the ions (and fast neutrals) extracted through the hole. We have developed a Monte Carlo simulation to follow the trajectories of ions and fast neutrals from the bulk plasma through the sheath and out the hole. Collisions with gas phase species and the walls of the hole are taken into account. We have also measured the energy and angular distribution of ions effusing from a hole on a wall in contact with a high density plasma. A hemispherical sectioned electrode is used as the detector. The hole diameter is varied from 25 to 1000 microns and the hole aspect ratio (depth to diameter) is varied from 0.25 to 10. The energy and angular distributions in both experimental data and simulations reflect the strong disturbance of the sheath when the hole size exceeds the local Debye length.