Metal-sheet-beam formation using an impregnated electrode-type liquid-metal ion source with a linear array of emission points

High current and sheet-shaped metal beams are required in ion implanters which utilize a mass separator. The present paper describes the profiles of the ion beams extracted from the impregnated electrode-type liquid-metal ion source with linear array of emission points (array source) and the formation of the sheet beams with a rectangular lens system. The experimental results indicated that the profiles of the extracted beamlet of array source without use of lens system have smaller divergences along the parallel direction with respect to the ion emission array. Since it has been clarified that the beamlet was convergent along the parallel direction, the focusing lens system was designed so as to converge the ion beam along the perpendicular direction. The profiles of the converged beams were also measured. As a result, it was found that the sheet beams were successfully formed and the thickness of the sheet-shaped beam is found to be about 2 mm. The present results demonstrated that this type of ion source could be utilized in a practical implanter.