Tuning the electrical performance of Ge nanowire MOSFETs by focused ion beamimplantation

Abstract

In this work, we demonstrate an approach to tune the electrical behavior of ourΩ-gated germanium-nanowire (Ge-NW) MOSFETs by focused ion beam (FIB) implantation.For the MOSFETs, 35 nm thick Ge-NWs are covered by atomic layer deposition (ALD) of a high-κ gate dielectric.With the Ω-shaped metal gate acting as implantation mask, highly doped source/drain (S/D) contactsare formed in a self-aligned process by FIB implantation. Notably, without any dopantactivation by annealing, the devices exhibit more than three orders of magnitude higherION currents, animproved ION/IOFF ratio, a higher mobility and a reduced subthreshold slope of140 mV/decade compared to identical Ge-NW MOSFETs without FIB implantation.