A method of doping a wafer includes implanting ions into a wafer by irradiating the wafer with an ion beam using an implantation device. The implantation device includes a filter frame and a filter held by the filter frame, wherein the filter is irradiated by the ion beam passing through the filter to the wafer, and the filter is arranged such that protruding microstructures of the filter face away from the wafer and towards the ion beam.