Plasma Doping—Enabling Technology for High Dose Logic and Memory Applications

As logic and memory device dimensions shrink with each generation, there are more high dose implants at lower energies. Examples include dual poly gate (also referred to as counter‐doped poly), elevated source drain and contact plug implants. Plasma Doping technology throughput and dopant profile benefits at these ultra high dose and lower energy conditions have been well established [1,2,3]. For the first time a production‐worthy plasma doping implanter, the VIISta PLAD tool, has been developed with unique architecture suited for precise and repeatable dopant placement. Critical elements of the architecture include pulsed DC wafer bias, closed‐loop dosimetry and a uniform low energy, high density plasma source. In this paper key performance metrics such as dose uniformity, dose repeatability and dopant profile control will be presented that demonstrate the production‐worthiness of the VIISta PLAD tool for several high dose applications.