Apparatus, system and method for energy spread ion beam
An ion implanter may include an ion source, arranged to generate a continuous ion beam, a DC acceleration system, to accelerate the continuous ion beam, as well as an AC linear accelerator to receive the continuous ion beam and to output a bunched ion beam. The ion implanter may also include an energy spreading electrode assembly, to receive the bunched ion beam and to apply an RF voltage between a plurality of electrodes of the energy spreading electrode assembly, along a local direction of propagation of the bunched ion beam.
1 . An ion implanter, comprising:
an ion source arranged to generate an ion beam;
a scanner disposed downstream of the ion source in a direction of travel of the ion beam; and
an energy spreading electrode assembly disposed downstream of the scanner, to receive the ion beam and to apply a time varying voltage bias signal between a plurality of electrodes of the energy spreading electrode assembly to generate an energy spread of the ion beam.
2 . The ion implanter of claim 1 , wherein the energy spread is dependent on the time varying voltage bias signal.
3 . The ion implanter of claim 1 , wherein the energy spread provides a first implant profile in a substrate for a nominal ion energy that is broader than a second implant profile in the substrate that is generated when a monoenergetic ion beam of the same nominal energy is directed to the substrate.
4 . The ion implanter of claim 1 , where the energy spread has an energy distribution equal to 1% to 30% of an initial energy of the ion beam.
5 . The ion implanter of claim 1 , wherein the time varying voltage bias signal is an RF voltage.
6 . The ion implanter of claim 1 , wherein the time varying voltage bias signal is an AC voltage.
7 . The ion implanter of claim 1 , wherein the scanner is operative to scan the ion beam at a first frequency, and wherein the time varying voltage bias signal is applied at a second frequency, at least ten times greater than the first frequency.
8 . The ion implanter of claim 7 , wherein the ion beam is elongated along a lateral direction, perpendicular to a local direction of propagation of the ion beam, wherein the energy spreading electrode assembly is arranged to apply a uniform energy spread to the ion beam across a width of the ion beam along the lateral direction.
9 . The ion implanter of claim 1 , further comprising a linear accelerator, disposed between the ion source and the energy spreading electrode assembly, and arranged to increase an energy of the ion beam.