Investigation of the Impact of Internal Metal Gate – From MFM Capacitors to Two-Layer-Stacked GAA Poly-Si NW FE-FETs

This work reports a comprehensive investigation on the negative-capacitance (NC) related ferroelectric FET (FE-FET) with Hf 1-x Zr x O 2 (HZO) with different sweeping sequences. Devices of the planar capacitor and Gate-All-Around (GAA) with 5.3 × 9 nm2 poly-Silicon nanowire (NW) channel were compared in detail. Despite the fact that PMA of 700°C exhibits the best ferroelectricity for the MFM capacitor, the results of NW FE-FETs are quite different owing to the stress-sensitive crystallization of HZO. We found the ZrO 2 , seedlayer, can significantly improve the crystallinity of HZO even with PMA-free. An internal-metal-gate (IMG) and/or 2-layer-stacked channel for GAA were demonstrated to improve performance. The inserted TiN as the IMG is found to gain superior S.S. avg of 43.85 mV/decade with 104 of I D . The I on of GAA can be further boosted by the stacked channel. In addition, the dipole polarization of FE is used to explain the results of examining different sweeping sequences.