Features, Regularities, and Prospects for Practical Application of High-Intensity Ion Implantation Methods

The article presents a review of works on high-intensity ion implantation with repetitively-pulsed metal and gas ion beams with a current density from several mA/cm2 to several A/cm2 with ion energies from units to 100 keV. Single-electrode systems for forming repetitively-pulsed beams of metal ions purified from microdroplet fractions and gases of high average and pulsed power densities have been considered. It has been shown that the pulse duration is limited due to the virtual anode appearance when forming intense metal ion beams from vacuum arc plasma by the ballistic focusing method at ion energies of up to several keV. The article has considered the methods that allow solving the problem of the virtual anode appearance and increasing the efficiency of ballistic focusing and ion beam transportation. The article has presented the data of experiments and numerical modeling proving that the efficient compensation of the space charge of the beam ions is achieved when forming metal ion beams with high pulse power density under conditions of increasing the average ion energy in the beam to several tens of keV. This is ensured by preliminary injection of plasma into the drift space in combination with additional generation of electrons due to ion-electron emission. Two methods of high-intensity implantation have been considered. At ion energies of up to several keV, the repetitively-pulsed implantation of metal and gas ions with a current density of up to 1 A/cm2 ensures forming ion-doped layers in metals and alloys with a thickness of tens and hundreds of micrometers. The features and regularities of ion alloying of various metals and alloys with high-frequency ion beams with a current density of up to 1 A/cm2 at low accelerating voltages and irradiation fluences of up to 1022 ion/cm2 have been discussed. The article has presented the experimental data on the modification of metals and alloys under conditions of synergy of high-intensity ion implantation and simultaneous repetitively-pulsed energy impact on the material surface by a beam with submillisecond duration with a power density from several tens to 200 kW/cm2. The data demonstrating the possibility of alloying Zr1%Nb alloy, titanium and aluminum with chromium, aluminum, titanium ions due to repetitively-pulsed heating of the surface layer to a depth of several microns have been presented for the first time.