Promised Design of Energy-Efficient Negative-Capacitance Vertical Tunneling FET

Abstract

Ferroelectric materials are promising resources for boosting the performance of line or vertical tunneling-field transistors (VTFETs) by diminishing the voltage requirements. Here, we propose a promising VTFET design which has the benefits of HZO thin films having 50% of Zr composition on Hafnium oxide as Hf0.5Zr0.5O2. The significance of negative capacitance (NC) from Hf0.5Zr0.5O2 on to VTFET is explored with the physical factors of the electric field and band-to-band tunneling. In addition, the significant factor of the internal-voltage due to NC is modeled using the metal-ferroelectric-insulator approach. The device on- and off-state currents are optimized with the key factor of vertical tunneling called overlapped source and drain regions for NCVTFET. Using an enhanced vertical tunneling area, hetero-structure (Si/SiGe), and ferroelectric options provides two-time improvement in I on by utilizing the ferroelectric rather than the nominal (without ferroelectric). The device also delivers 40–145 GHz of frequency with low orders (<1.0 fF) of gate-capacitance. The device provides ten-time improvement in I on and two-order reduction in energy-efficiency compared to the explored ferroelectric structure.