Methods and apparatus for oxygen implantation
AssigneeVarian Semiconductor Equipment Associates, Inc.
InventorJaime M. Reyes
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Abstract
An oxygen ion containing plasma is generated using a hot filament ion source. The oxygen ions in the plasma come from an oxide source (e.g., a metal oxide) which has a lower free energy of formation than that of the filament metal oxide (e.g., WO3) at the operating temperatures of the ion source. Consequently, oxidation of the filament and other metal components of the arc chamber is limited, or even prevented. Thus, the invention can advantageously lead to longer filament lives as compared to certain conventional processes that generate oxygen plasmas using hot filament sources.
Claims28
An ion source comprising:
- a chamber;
- a metal filament housed within the chamber;
- and
- an oxygen source component housed within the chamber, the oxygen source component comprising an oxide compound which has a lower free energy of formation than the oxide of the filament metal over the operating temperature range of the ion source for enabling the implantation of oxygen ions while limiting oxidation of the filament metal.
An ion source as in claim 7, wherein the metal filament comprises tungsten.
An ion source comprising:
- a chamber;
- a metal filament housed within the chamber;
- an oxygen source component housed within the chamber, the oxygen source component comprising a metal oxide of the group consisting of Ga2O3, B2O3, SiO2, Al2O3, TiO2, and MgO for enabling the implantation of ions while limiting oxidation of the metal filament;
- and
- a source gas supply connected to the chamber.
A repeller unit for an arc chamber of an ion source, the repeller unit comprising:
- a conductor plate;
- a connector connecting the conductor plate to a voltage source;
- and
- an ion source component mounted on the conductor plate and exposed to the interior of the arc chamber when the repeller unit is mounted therein, the ion source component comprising a solid oxide compound which is a member of the group consisting of Ga2O3, B2O3SiO2, Al2O3, TiO2, ZrO2, and MgO for enabling the implantation of ions while limiting oxidation of a filament metal of the ion source.
A method of generating oxygen ions in an arc chamber of an ion source having a metal filament therein, the method comprising:
- providing a solid oxygen source within the arc chamber, the solid oxygen source comprising an oxide compound which has a lower free energy of formation than the oxide of the filament metal over the operating temperature range of the arc chamber for limiting oxidation of the filament metal;
- feeding a source gas into the chamber;
- passing current through the filament;
- and
- causing electrons to be emitted from the filament, the electrons colliding with source gas molecules to create source gas ions that chemically interact with the solid oxygen source to form oxygen ions.
A method of generating an ion beam of a desired species, selected from the group consisting of Al, Ga, B, Si, Ti, Zr, and Mg ions, in an ion implanter apparatus comprising an ion source including an arc chamber having an electron emitting filament therein of an oxidizable metal, the method comprising
- providing a solid oxide of the desired species in the arc chamber,
- feeding a source gas into the chamber,
- generating an arc in the arc chamber by thermionic electron emission from the filament for enabling the implantation of ions while limiting oxidation of the filament,
- extracting an ion beam comprising ions of the desired species from said arc chamber, and
- separating the desired species ions from other components of the ion beam to form said ion beam of said desired species.
Dependencies are inferred from the claim text.