Ion implantation system and control method

A method of ion implantation by producing a high brightness ion beam that extends along an axis by ionizing molecules of a gas or vapor, the molecules containing an implantable species, the method comprising:

• providing an ionization chamber having a restricted outlet aperture,
• providing in said ionization chamber said gas or vapor at a pressure substantially higher than the pressure within an extraction region into which the ions are to be extracted external to the ionization chamber,
• by direct electron impact ionization by primary electrons, ionizing the gas or vapor in a region adjacent the outlet aperture of the ionization chamber in a manner to produce ions from the molecules of the gas or vapor to a density of at least about 1010 cm−3 at the aperture while maintaining conditions that limit the transverse kinetic energy of the ions to less than about 0.7 eV,
• the width of the ionization volume adjacent the aperture, in which said density of ions is formed, being limited to a width less than about three times the corresponding width of the outlet aperture;
• and conditions within the ionization chamber being maintained to prevent formation of an arc discharge,
• by an extraction system, extracting ions formed within the ionization chamber via the outlet aperture into the extraction region downstream of the aperture,
• thereafter, with ion beam optics, transporting the beam to a target surface, and
• implanting the ions of the transported ion beam into the target.