An alternative dopant-measurement method for analyzing ULE implant

As seen from the International Technology Roadmap for Semiconductors (ITRS) [1], the source/drain junction depth is being reduced each year in order to continue MOS transistor scaling. This year, leading-edge foundries and integrated device manufacturers (IDMs) are scheduled to move 65nm processes into pre-production, while simultaneously developing 45nm processes in R&D. In designing and manufacturing such VLSI devices, the junction depth needs to be kept below 50nm, and doping concentrations in the channel must be high and accurate. To obtain an ultra shallow junction (USJ), the most fundamental trend in ion implantation today is to move implant energies lower so that possible surface damage and channeling can be minimized [2]. This trend makes the determination of USJ depths and implant doses increasingly difficult.