ION IMPLANTATION DEVICE AND METHOD OF MANUFACTURING SEMICONDUCTOR BY IMPLANTATION OF BORON HYDRIDE CLUSTER IONS

PROBLEM TO BE SOLVED: To provide a magnetic yoke assembly for use in an ion source generating cluster ions by electron impact ionization.SOLUTION: A magnetic yoke assembly 500 is configured by arranging a pair of permanent magnets 510A and 510B between yokes 520A, 520B formed from a pair of magnetic pole pieces. The pair of magnetic pole pieces have openings 530A, 530B through which an electron beam passes. With such a configuration, a uniform magnetic field parallel to the electron beam is generated in an ionization chamber. Electrons in the electron beam incident from the openings follow a helical trajectory along the direction of lines of magnetic fields, and the electron beam is confined around the lines of magnetic fields.