Multidomain Dynamics of Ferroelectric Polarization and its Coherency-Breaking in Negative Capacitance Field-Effect Transistors

摘要

In this paper, for the first time, we clarified the multidomain dynamics of ferroelectric polarization in the Negative Capacitance Field-Effect Transistors (NCFETs) by an in-house Technology Computer-Aided Design (TCAD) module. It enables self-consistent simulations among the time-dependent Landau-Khalatnikov equation and the other equations that govern operation of FETs. Our simulation reveals that domain-wall thickness T_dw, which reflects a correlation strength between domains predominates coherency of the NC polarization. In a strong correlation (large T_dw) case, a coherent NC polarization is realized at least to a degree of T_dw. On the other hand, in a weak correlation (small T_dw) case, perturbation from peripherals easily leads to incoherence of polarization, where a uniform polarization is split into multiple spontaneous polarization domains. This coherency breaking found to give rise to deteriorated voltage amplification of NC. Design methodology to maintain the NC coherency is also proposed.