Unveiling the reliability of negative capacitance FinFET with confrontation of different HfO2-ferroelectric dopants

Abstract

The CMOS compatibility of Negative Capacitance (NC) FETs has been enhanced tremendously after introducing a thin film-doped HfO₂ as a ferroelectric (FE) layer. For a given FE layer, the NC property is governed by specific HfO₂ dopants (e.g., La, Zr, Al, Sr, Gd, Y, and Si). Thus, the TCAD simulation considerably depends on the dopant-specific Landau parameters (${\alpha }_x,{\beta }_x,{\gamma }_x,{\rho }_x,g_x$), and its solidity needs proper attention. Further, the reliability of the NC devices is severely affected by process variations, i.e., interface trap charges, work function variation, random dopant fluctuation, and ambient temperature (external), which modulates the device threshold voltage (V_th); in turn, the device aging. In this paper, using well-calibrated TCAD models, we investigated reliability for the different dopant-specific NC-FinFET, in terms of V_th, ON current (I_ON), and OFF current (I_OFF) modulation induced by: (i) the interface trap variability (ITV) considering the different trap concentration and energy location; (ii) the work function variability (WFV) considering different metal grain sizes (G_r); (iii) the random dopant fluctuations (RDF); and (iv) the ambient temperature. In this way, the device aging is calculated by inspecting V_th shift by $\pm 50mV$. These investigations pave the path for realizing a reliable NC-FinFET design.