  Tri-gate ferroelectric FETs with Hf0.5Zr0.5O2 gate insulator for memory and
neuromorphic applications are fabricated and characterized for multi-level
operation. The conductance and threshold voltage exhibit highly linear and
symmetric characteristics. A compact analytical model is developed to
accurately capture FET transfer characteristics, including series resistance,
coulombic scattering, and vertical field dependent mobility degradation
effects, as well as the evolvement of threshold voltage and mobility with
ferroelectric polarization switching. The model covers both sub-threshold and
strong inversion operation. Additional measurements confirm ferroelectric
switching as opposed to carrier-trapping-based memory operation. The compact
model is implemented in a simulation platform for online training of deep
neural networks.
