Apparatus and methods for ion implantation

In a method for operating an ion source system comprising an ion source having an ion emitting region, an extraction electrode positioned in the vicinity of said ion emitting region, and a second electrode positioned substantially adjacent said extraction electrode, the steps of:

• applying a preanalysis acceleration voltage to said ion source;
• applying to said extraction electrode a bias potential having a value relative to said preanalysis acceleration voltage to extract and accelerate ions from said source;
• and
• applying to said second electrode a bias potential having a value relative to said bias potential value on said extraction electrode of the same order of magnitude as the value of the bias potential on the extraction electrode relative to the preanalysis acceleration voltage, to reduce substantially the velocity of ions travelling between said extraction electrode and said second electrode.

In a method for implanting ions of substantially a single preselected ions species into a target element, the steps of:

• generating an ion beam of substantially uniform velocity and having a plurality of ion species therein, including said preselected ion species;
• analyzing said ion beam to separate ions having different values of charge to mass ratio into different beam paths;
• selecting from a group of beam resolving elements a particular beam resolving element;
• and
• positioning said selected beam resolving element in the path of the ion beam of said preselected ion species to pass said ions to said target element.

In an ion source system, a source chamber with an elongated ion exit aperture in one wall thereof;

• an elongated filament-cathode disposed lengthwise within said source chamber;
• means applying a current generating electrical potential difference across said filament-cathode;
• means applying an arc creating bias between said chamber and said filament-cathode to generate ions within said chamber;
• and means applying a magnetic field parallel to said filament-cathode with a non-uniform field strength to counteract non-uniform ion generating characteristics from one end of said source to the other.

In a method for generating an ion beam of selecting energy for an ion implantation system, the steps of:

• creating a plasma of ions within a generally confined volume;
• extracting a beam of ions from said plasma with an accelerating voltage;
• and
• decelerating said beam of ions with a substantial decelerating voltage relative to said accelerating voltage, said deceleration voltage being of the same order of magnitude as said accelerating voltage.

In a method for implanting ions of substantially a single preselected ion species into a target element, the steps of:

• generating an ion beam having a plurality of ion species therein, including said preselected ion species;
• analyzing said ion beam to separate ions having different values of charge to mass ratio into different focused ion beam paths;
• and
• passing the focused ion beam of said preselected ion species through a preselected one of a plurality of beam resolving elements into said target element.