Reliability of Multiple-Layer Stacked Gate-All-Around Poly-Si Nanosheet Channel Ferroelectric HfxZr1-xO2FETs With NH3 Plasma Treatment

In this work, multiple-layer stacked gate-all-around polycrystalline silicon (poly-Si) nanosheet channel ferroelectric-Hf
_x
Zr
_1-x
O
₂
(FE-HZO) FETs without and with NH
₃
plasma treatment at both the TiN/HZO and ZrO
₂
/TiN interfaces were successfully fabricated, and their reliability was investigated and discussed for the first time. The devices after a positive gate bias stress (PGBS) test revealed that the average subthreshold swing (SS) degradation and the threshold voltage shift can be considerably improved by NH
₃
plasma treatment at both the TiN/HZO and ZrO
₂
/TiN interfaces. Furthermore, the devices after NH
₃
plasma treatment show the significantly reduced degradation rates which are related to transconductance, ON-current, and gate leakage current. By using NH
₃
plasma treatment at both the TiN/HZO and ZrO
₂
/TiN interfaces to significantly enhance the gate-stack quality and effectively suppress the generation of oxygen vacancies and interface traps during the PGBS test, the devices exhibit an excellent SS of 51.4 mV/dec., a high driving current of
$49.5 \mu \text{A}/\mu \text{m}$
, and a strong PGBS immunity, making them attractive for monolithic 3-D integrated circuit applications.