IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Thursday Sessions
       Session TF-ThP

Paper TF-ThP8
Velocities and Ionization Degree of Vapor Stream Produced from Evaporation Source using Porous Rod by Electron Beam Heating

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Thin Film Deposition/Carbon-Containing Films Poster Session
Presenter: H.M. Ohba, Japan Atomic Energy Research Institute
Authors: H.M. Ohba, Japan Atomic Energy Research Institute
T. Shibata, Japan Atomic Energy Research Institute
Correspondent: Click to Email
A metal vapor was produced by electron beam heating with high thermal efficiency using a hearth liner and a porous rod for copper and cerium. While the top surface of the porous rod was heated by electron beam, the molten evaporation material surrounding the rod was transferred to the top surface by capillarity; then the atomic vapor stream was produced from the top surface. The ionization degree and the vapor velocities were measured with Langmuir probes, and a microbalance or laser induced fluorescence. The vapor characteristics were compared by evaporation from the bare water-cooled copper crucible. The ionization degree in the metal vapor is proportional to the electron beam current of the electron gun. In the case of evaporation from the porous rod, so a large amount of vapor flux can be produced at low electron beam current that the degree of ionization of metal vapor in the vicinity of the source is very low. The velocities of vapor produced from the porous rod were lower than that from the bare crucib le even at high vapor flux. The lower velocity for the porous rod was explained as follows. The excitation and ionization energies of the atoms evaporated by electron impact are converted to the kinetic energy of the vapor atoms by atom-atom collision. In the case of the porous rod, the rate of electron impact ionization of the evaporated atoms is lower than that of the bare crucible.