PURPOSE: To cut down primary factors of generating blur of an ion beam so as to reduce contamination of a path of the ion beam by providing an electron gun for generating the pulsing electron beam ionizing a given gas and a beam control supply for feeding a pulsing voltage.
CONSTITUTION: An electron gun consists of a cathode 32 having an ion passing hole in the center of an ion supply 31 and being provided with an electron emitting surface, and a grid 33 and an outlet electrode 34, serving as an electron beam control electrode. A non-illustrated ion beam controlled and formed by said electron gun is further accelerated by an anode 35 to ionize the given gas in an ionization space between the anode 35 and an electron collector 39. Further, a pulsing control voltage is impressed between the grid 33 and the cathode 32 from a DC bias power supply 50 and a pulse power supply 51 to generate a pulsing electron beam. Thereby, without providing a deflection means and a blanking target the primary factors of generating blur of an ion beam can be cut down while reducing contamination of an ion beam path and shortening the ion beam path.
KAWASE YUTAKA
KOBAYASHI HIDEKI
