Highly scaled (Lg ∼ 56 nm) gate-last Si tunnel field-effect transistors with ION > 100 μA/μm

Planar band-to-band tunneling FETs (TFETs) have been fabricated on silicon-on-insulator (SOI) substrates using conventional CMOS technologies with a highly scaled sub-60 nm gate length (effective gate length [Lg] ∼ 40 nm due to an overlap between the source and gate) and different anneal sequences. The optimal anneal sequence including spike and flash annealing resulted in a drive ON current (ION)) > 100 μA/μm with ION/IOFF > 105 at a drain bias of −1 V. The devices exhibited negative differential resistance and non-linear subthreshold temperature dependencies, consistent with the band-to-band tunneling mechanism. Simulations using a 2-D TCAD simulator, MEDICI, agreed with experimental data, demonstrating the possibility of Si tunnel transistors in logic applications.