Ion gun

An Ion Gun typically is an instrument that generates a beam of heavy ions with a well defined energy distribution. The <a href="/facts/Ion_beam/e23WW7uC">ion beam</a> is produced from a plasma that has been confined within a volume. Ions of a particular energy are extracted, accelerated, collimated and/or focused. The ion gun is composed of an <a href="/facts/Ion_source/3hP3h1sM">ion source</a>, extraction grid structure and a collimation/lensing structure. The plasma can be made up of an inert or reactive gas (e.g. N+ and O+) or an easily condensable substance (e.g. C+ and B+). The plasma can be formed from molecules that contain the substance which will form the beam, in which case, these molecules must be fragmented then ionized (e.g. H and CH4 can together be fragmented and ionized to create a beam for depositing diamond-like carbon films).
The ion <a href="/facts/Current_density/IlUKSe2B">current density</a> (or similarly the ion flux), the ion energy spread, and the <a href="/facts/Optical_resolution/TcLkPYFw">resolution</a> of the ion beam are key factors in ion gun design. The ion current density is controlled by the <a href="/facts/Ion_source/3hP3h1sM">ion source</a>, the energy spread is determined primarily by the extraction grid, and the resolution is determined primarily by the optical column.
The ion gun is an important component in <a href="/facts/Surface_science/WTENdutJ">surface science</a> in that it provides the scientist with a means to sputter etch a surface and generate an elemental or chemical depth profile. Modern ion guns can produce beam energies from 10eV to more than 10keV.

Ion gun open-in-new

Ion gun