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Apparatus for Producing Ionized Metal Vapor

IP.com Disclosure Number: IPCOM000108250D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Roberts, S: AUTHOR [+3]

Abstract

Relatively high ionization efficiency is achieved in a vacuum evaporated metal vapor stream. Independent control of vaporization rate and ionization efficiency is achieved by a combination of radio frequency (RF) source heating control and controlled current electron bombardment of the vapor stream for ionization control. Highly efficient ionization of the vapor stream results from an interaction of RF-induced current in the ionized vapor stream. A resultant elongated path of electrons traveling near the induced current path increases probability of vapor ionization. This ionized vapor source may be used in applications, e.g., high density and high conductivity metal film formation by accelerated metal ion bombardment of condensing films.

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Apparatus for Producing Ionized Metal Vapor

       Relatively high ionization efficiency is achieved in a
vacuum evaporated metal vapor stream.  Independent control of
vaporization rate and ionization efficiency is achieved by a
combination of radio frequency (RF) source heating control and
controlled current electron bombardment of the vapor stream for
ionization control.  Highly efficient ionization of the vapor stream
results from an interaction of RF-induced current in the ionized
vapor stream.  A resultant elongated path of electrons traveling near
the induced current path increases probability of vapor ionization.
This ionized vapor source may be used in applications, e.g., high
density and high conductivity metal film formation by accelerated
metal ion bombardment of condensing films.

      Referring to the figure, metal 2 contained in crucible 4 is
heated by radiation and conduction from graphite susceptor 6 which,
in turn, is heated by water-cooled RF induction coil 8.  The
uppermost portion of coil 8 is held at ground potential.  Grounded
shield 10, having an opening through which metal vapor escapes
upward, is supported above the RF-heated vacuum deposition source.
Tungsten filament 12, having its coil in closest proximity to shield
10 held at ground potential, is heated by variable, low voltage,
current source 14.  Conductive susceptor 6 is physically supported by
electrical insulator 16 which rests on baseplate 18. This allows
relatively high DC...