Planar Metal–Oxide–Semiconductor Field-Effect Transistors with Raised Source and Drain Extensions Fabricated by In situ Boron-Doped Selective Silicon Epitaxy

Abstract

Junction depth and parasitic resistance have a trade-off relationship. To improve this relationship, in situ boron-doped selective Si epitaxy was used to fabricate metal–oxide–semiconductor field-effect transistors (MOSFETs) with raised source and drain extensions and a facet. The amount of boron diffusion was small and the MOSFET also had low extension sheet resistance. Furthermore, with the optimization of four process parameters, spike rapid thermal annealing (RTA) temperature, halo dose, impurity concentration introduced by in situ doping, and epitaxial Si thickness, the relationship between the gate length at Ioff=100 nA/µm and the drive current at Ioff=100 nA/µm was improved.