A Comprehensive Study of Polymorphic Phase Distribution of Ferroelectric-Dielectrics and Interfacial Layer Effects on Negative Capacitance FETs for Sub-5 nm Node

摘要

The impact of a realistic representation of gate-oxide granularity on negative-capacitance (NC) FETs at sub-5nm node is studied by a newly developed thermodynamic energy model based on the first principle calculation (FPC). For the first time, the calculation fully couples the Landau-Khalatnikov (L-K) equation with grain-size effect equation in NC-FETs. It explains the experimental results in phase transition and reveals excellent immunity against depolarization in ferroelectric (FE) layer owing to dopant concentration and stress in thin films. A sub-5nm node (LG=10nm) NC-FET with thin FE layer (T_FE~2nm) is integrated to achieve low subthreshold slope (SS) of 52mV/dec via a 1.9GPa-tensor stressed interfacial layer (IL) and 12% Zr-doped HfO₂.