Low Temperature Phosphorus Activation in Germanium through Nickel Germanidation for Shallow n⁺/p Junction

Abstract

To realize scaled germanium (Ge) complementary metal oxide semiconductor (CMOS), ultra shallow junctions, where impurities are sufficiently activated, are strongly required. However, it is not easy for n-type impurities to achieve both high activation and low diffusion in Ge, as long as we adopt a conventional thermal annealing process. In this paper, both activation and segregation of phosphorus at a nickel mono-germanide/Ge interface through a germanidation process at 300 °C are demonstrated. This low temperature activation in Ge-CMOS fabrication is suitable for the self-aligned gate first process without degrading the dielectrics/Ge interface of Ge gate stacks.