Reliability of Multiple-Layer Stacked Gate-All-Around Poly-Si Nanosheet Channel Ferroelectric Hf_xZr_1-xO₂FETs With NH₃Plasma Treatment

In this work, multiple-layer stacked gate-all-around polycrystalline silicon (poly-Si) nanosheet channel ferroelectric-HfxZr1-xO2 (FE-HZO) FETs without and with NH3 plasma treatment at both the TiN/HZO and ZrO2/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 NH3 plasma treatment at both the TiN/HZO and ZrO2/TiN interfaces. Furthermore, the devices after NH3 plasma treatment show the significantly reduced degradation rates which are related to transconductance, ON-current, and gate leakage current. By using NH3 plasma treatment at both the TiN/HZO and ZrO2/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 μA/μm, and a strong PGBS immunity, making them attractive for monolithic 3-D integrated circuit applications.