Ion sources for energy extremes of ion implantation (invited)

Abstract

For the past four years a joint research and development effort designed to develop steady state, intense ion sources has been in progress with the ultimate goal to develop ion sources and techniques that meet the two energy extreme range needs of meV and hundreads of eV ion implanters. This endeavor has already resulted in record steady state output currents of high charge state of antimony and phosphorus ions: P(2+) [8.6 pmA (particle milliampere)], P(3+) (1.9 pmA), and P(4+) (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb(3+)Sb(4+), Sb(5+), and Sb(6+) respectively. For low energy ion implantation, our efforts involve molecular ions and a novel plasmaless/gasless deceleration method. To date, 1 emA (electrical milliampere) of positive decaborane ions was extracted at 10 keV and smaller currents of negative decaborane ions were also extracted. Additionally, boron current fraction of over 70% was extracted from a Bernas-Calutron ion source, which represents a factor of 3.5 improvement over currently employed ion sources.

Molecular phosphorus ion source for semiconductor technology

“…4 Figure 2 shows the ion beam spectrum for two operating modes of the discharge system. The oscillogram 3 is for the first mode with electron oscillation in which the anticathode is connected to the cathode or is at floating potential, whereas oscillogram 2 is for the mode with a plasma beam discharge with no electron oscillation in which the anticathode is connected to the anode.…”

Compact, energy EFFICIENT neutron source: enabling technology for various applications

“…Next to be analyzed is a case of deuterium ions in 100% ionized plasma like from a hollow cathode arc [31][32][33][34][35][36] with temperatures in the range of 12 -15 eV, and densities exceeding 1x10 14…”

“…A major difficulty in evaluating this scenario is determination of equilibrium electron temperature of magnetically confined plasma targets 33,36 that are heated by an ion beam, for which no beam heating data is available (in reference 36 e.g. 8 MeV beams with currents of only about a μA were used).…”

“…power required for ionizing the original plasma, which does not factor in beam power deposition/loss balance; equivalent to filament power in other schemes) and radiation losses. BNL experimental data is available for 1 inch-diameter magnetized plasma 33,36 for open geometry solenoidal plasma 36 and for a closed loop Dshaped solenoidal magnetic field 33 . In these experiments, like in many hollow cathode arcs, plasma densities of 2x10 14 cm -3 have been routinely reached.…”