Method and apparatus for plasma source ion implantation

A method of implanting ions in a target object comprising the steps of:

• (a) providing an enclosing chamber having walls of electrically conductive material;
• (b) suspending a target object within the chamber spaced away from the walls of the chamber;
• (c) evacuating the interior of the chamber to a very low base pressure;
• (d) forming a plasma of ions in the chamber around the target object;
• (e) independently of forming the plasma, applying a pulse of high voltage between the chamber walls and the target object at a voltage sufficient to implant ions from the plasma into the target object.

A method of implanting ions in a target object comprising the steps of:

• (a) providing an enclosing chamber having walls of electrically conductive material;
• (b) suspending a target object within the chamber spaced away from the walls of the chamber;
• (c) evacuating the interior of the chamber to a very low base pressure;
• (d) forming a plasma of ions in the chamber around the target object;
• (e) applying repetitive pulses of high voltage between the chamber walls and the target object independently of the forming of the plasma to draw ions in the plasma to the target object at a voltage sufficient to implant ions from the plasma into the target object, the width of the pulses being selected such that the plasma sheath surrounding the target object does not expand to contact the enclosure walls during the pulse.

A method of implanting ions in a target object comprising the steps of:

• (a) providing an enclosing chamber having walls of electrically conductive material;
• (b) suspending a plurality of target objects within the chamber spaced away from the walls of the chamber and from each other;
• (c) evacuating the interior of the chamber to a very low base pressure;
• (d) forming a plasma of ions in the chamber around the target objects;
• (e) applying repetitive pulses of high voltage between the chamber walls and the target objects independently of the forming of the plasma to draw ions in the plasma to the target object at a voltage sufficient to implant ions from the plasma into the target objects, the width of each pulse of high voltage selected such that the plasma sheath surrounding each target object does not expand during the pulse to contact the plasma sheath surrounding another target object or to contact the walls of the chamber.

An apparatus for implanting ions in a target object comprising:

• (a) electrically conductive enclosure walls defining an enclosing chamber surrounding a sealed space;
• (b) means for supporting a target object within the enclosing chamber at a position spaced away from and electrically isolated from the enclosure walls of the chamber and for providing an electrical connection between the target object so supported and the exterior of the chamber;
• (c) means for forming a plasma of ions of a selected material within the enclosing chamber around the target object;
• (d) means for evacuating the interior of the enclosing chamber to a desired low pressure level;
• and
• (e) means, independent of the means for forming a plasma, for applying a pulse of voltage between the enclosure walls and the target object sufficient to implant ions from the plasma into the target object.