About the EventIon implantation technique is essential to modern integrated-circuit (IC) fabrication and pre-cision materials modification (PMM). Doping or otherwise modifying semiconductor materi-als involves generating an ion beam and steering it into the substrate so that the ions come to rest beneath the surface. At low implant energies (<5 keV), traditional beamline tech-nologies suffer from low beam transport efficiency due to space charge related difficulties. New beamline implanters, running in deceleration mode, can achieve high beam currents, but are still limited by space charge expansion at ultra low energies and by charge exchange collisions between ions and residual neutrals. Consequently plasma based implantation technologies were developed to enable high dose implants (>5x1015/cm2) at low energy (0.02< <10 keV). The AMAT/Varian PLAsma Doping system (PLAD), has been developed with a unique architecture suited for precise and repeatable dopant placement for PMM. Critical elements include a pulsed DC wafer bias, modulated rf power, closed-loop dosimetry and a uniform low energy, high density plasma source. In this talk key performance parame-ters such as dose uniformity, dose repeatability, dopant angle and profile control will be pre-sented. The complex plasma chemistry, electron and ion transport in these systems will be discussed. Calculations of rate coefficients for radical ion production in BF3 will be pre-sented. Beamline implanters and plasma doping devices will be compared. |
