High-Performance Germanium p- and n-MOSFETs With NiGe Source/Drain

Abstract

In this paper, we report Ge p- and n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with NiGe source/drain (S/D) with high performance and low leakage current. The forward/reverse current ratio of the NiGe/n-Ge and NiGe/p-Ge junctions were similar to 10(5) and similar to 2 x 10(4) at vertical bar V vertical bar = +/- 1 V, respectively. Interface state densities Dit of Al2O3/GeO2/Ge stack is improved to be around 10(12)/eV(-1) cm(2) near the midgap after forming gas annealing; the gate-stack also shows excellent reliability under constant field stressing. Both p- and n-channel MOSFETs show sufficiently high ION/IOFF ratio. High driving current of similar to 9 and similar to 4 mu A/mu m at vertical bar V-GS - V-T vertical bar = +/-0.8 V and V-DS vertical bar = +/- V is obtained, respectively, for p- and n-MOSFETs. Moreover, S/D series resistance R-SD of the p- and n-MOSFET is reduced by similar to 25% and similar to 42% as compared with that of the transistors with conventional p/n junctions.