Apparatus and techniques for generating bunched ion beam

An ion implantation system, comprising:

• an ion source to generate a continuous ion beam;
• a drift tube assembly, disposed downstream of the ion source, the drift tube assembly comprising:
• a first grounded drift tube, arranged to accept the continuous ion beam;
• an AC drift tube assembly, arranged downstream to the first grounded drift tube;
• and
• a second grounded drift tube, downstream to the AC drift tube assembly;
• and
• an AC voltage assembly, arranged to send to the AC drift tube assembly a first AC voltage signal at a first frequency, and a second AC voltage signal at a second frequency, wherein the second frequency comprises an integral multiple of the first frequency, and wherein the second frequency is twice the first frequency, wherein the AC voltage assembly is arranged to send a third AC voltage signal at a third frequency to the AC drift tube assembly, the third frequency being three times the first frequency.

A method of treating an ion beam, comprising:

• generating the ion beam as a continuous ion beam;
• receiving the continuous ion beam in a multi-ring drift tube assembly;
• conducting the ion beam through a first AC drift tube of the multi-ring drift tube assembly while applying a first AC voltage signal at a first frequency to the first AC drift tube;
• and
• conducting the ion beam through a second AC drift tube of the multi-ring drift tube assembly, downstream of the first AC drift tube while applying a second AC voltage signal at a second frequency to the second AC drift tube, the second frequency comprising an integral multiple of the first frequency, wherein the ion beam is output from the multi-ring drift tube assembly as a bunched ion beam, wherein the continuous ion beam comprises an ion energy of at least 250 keV.