Impact of HZO and HSO thin film ferroelectric on FDSOI NCFET

In this work, negative capacitance effect of MFMIS type FDSOI NCFET is investigated considering two well known thin film ferroelectric materials HZO (Zirconium doped HfO2) and HSO (Silicon doped HfO2). The investigations are carried out in a TCAD environment where the gate charge is extracted from the TCAD simulation and subsequently computed ferro voltage across the ferroelectric capacitor to find the effective gate voltage in the gate-stack. The obtained values are then subjected to variation in ferroelectric thickness to predict the onset of hysteresis for both HZO and HSO ferroelectric materials. It has been observed that the HZO ferroelectric offers superior improvement in sub-threshold slope (SS), peak-gm and off-current at lower ferroelectric thickness with the expense of gate-induced-drain-leakage (GIDL) and lower endurance to hysteresis. On the other hand, the HSO ferroelectric predicts improvement in SS, peak-gm and off-current with superior control in GIDL where the device has higher endurance towards hysteresis in-spite of ferroelectric thickness under sub-10 nm regime.

I. Introduction

INVENTION of MOSFET in the mid 20^th century lead the way to revolutionary enhancements in integrated circuit (IC) industry. This IC revolution motivated Gordon Moore to propose Moore's law [1] with a bold prediction of doubling the transistor count in an IC for every two years. Although, it is an essential design law implemented by major foundries. It has some fundamental physical limitations, one of which is Boltzmann's limit or Boltzmann's tyranny [2] that states the sub-threshold slope (SS) can not go below 60 mY/dec. at room temperature. The simplest way to pre-eminent and overcome this fundamental limit is by stacking a ferroelectric negative capacitor in the gate-stack of a MOSFET device. This approach can further help to achieve hyper-scaling to keep Moore's law alive [3].