Impact of the gate stack on the electrical performances of 3D multi-channel MOSFET (MCFET) on SOI

In this study, we integrate and compare the electrical performances of metal/high-K embedded gates in 3D multi-channel CMOSFETs (MCFETs) on SOI. The electrical characteristics of embedded gates obtained by filling cavities with TiN/HfO2, TiN/SiO2 or N+ poly-Si/SiO2 are compared to a planar reference. In particular, we investigate electron and hole mobility behaviours (300 K down to 20 K) in embedded and planar structures, the gate leakage current and the negative bias temperature instability (NBTI). Despite a lower mobility, TiN/HfO2 gate stack demonstrates the best ION/IOFF compromise and exhibits NBTI life time higher than 10 years up to 1.3 V.