Application of digital frequency and phase synthesis for control of electrode voltage phase in a high-energy ion implantation machine, and a means for accurate calibration of electrode voltage phase

An ion implanter comprising:

• an ion source adapted to direct charged ions having an initial mass and energy along a path;
• a mass analyzer downstream of the ion source for selecting ions based on the mass and energy of the ions;
• a multi-stage linear accelerator downstream of the mass analyzer comprising:
• a plurality of acceleration gaps;
• and
• a plurality of RF electrodes for accelerating the ions therebetween;
• wherein each stage of the multi-stage linear accelerator has at least one RF electrode and an acceleration gap adjacent to the electrode, and wherein each RF electrode is operatively associated with an accelerator energy source adapted to create an accelerating alternating electric field to accelerate the ions to a second energy;
• an end station adapted to position a workpiece so that the accelerated charged ions impact the workpiece;
• and
• a direct digital synthesis (DDS) controller coupled to the energy source and adapted to digitally synchronize a frequency and phase of the electric fields of each stage in the linear accelerator, the DDS controller comprising:
• a plurality of digital phase synthesis (DPS) circuits individually coupled to each of the plurality of RF electrodes to modulate the phase of the voltage applied to each RF electrode;
• and
• a digital frequency synthesis circuit (DFS) connected to each of the plurality of DPS circuits and adapted to digitally synthesize a master frequency and phase applied to each of the DPS circuits.