Decel lens system for low-energy ion implantation with high dose uniformity

In this paper we report on the design of a decel lens system for low energy ion implantation. The novel lens system consisting of a converging and a diverging lens in a compact arrangement allows to compensate the spherical aberration. Therefore implantation into large areas at low energies can be performed with high dose uniformity. The implantation chamber with the decel lens system is fitted to the beamline 2 of the medium energy implanter DANFYSIK 1090 at the Forschungszentrum Rossendorf. Using a beam energy of 30 keV the ions can be decelerated up to 2 keV with a dose uniformity of <5% for 100 mm diameter.