Ferroelectric Polarization Switching of Hafnium Zirconium Oxide in a Ferroelectric/Dielectric Stack

Abstract

The ferroelectric polarization switching in ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2, HZO) in the HZO/Al2O3 ferroelectric/dielectric stack is investigated systematically by capacitance-voltage and polarization-voltage measurements. The thickness of dielectric layer is found to have a determinant impact on the ferroelectric polarization switching of ferroelectric HZO. A suppression of ferroelectricity is observed with thick dielectric layer. In the gate stacks with thin dielectric layers, a full polarization switching of the ferroelectric layer is found possible by the proposed leakage-current-assist mechanism through the ultrathin dielectric layer.Theoretical simulation results agree well with experimental data. This work clarifies some of the critical parts of the long-standing confusions and debating related to negative capacitance fieldeffect transistors (NC-FETs) concepts and experiments.

Ferroelectric Switching in Trilayer Al2O3/HfZrOx/Al2O3 Structure

“…Similar to this work, bilayer systems with HZO/AlO ferroelectric/dielectric structures were recently reported [ 34 , 35 ]. Unlike the dielectric, ferroelectric (or antiferroelectric)-related layers such as ZrO 2 serving as a seed layer were introduced to promote the orthorhombic phase in the doped HfO 2 film [ 36 , 37 ].…”

Hafnium Oxide‐Based Ferroelectric Devices for Computing‐in‐Memory Applications

“…Such a dependence of the coercive electric field and remnant polarization on the voltage sweep range is similar to that in other published works. [33,34] In the process of ferroelectricity formation, the phenomenon of ferroelectric domain switching occurs which is realized by the appearance and development of new domains and the movement of domain walls under the application of an external electric field. Therefore, increasing the electric field strength is beneficial to enabling a more thorough ferroelectric domain switching.…”

The Impact of Channel Semiconductor on the Memory Characteristics of Ferroelectric Field-Effect Transistors

“…The ferroelectricity in hafnium oxide (HfO 2 ) was revealed by introducing certain dopant, such as Si, Zr, Al etc., to stabilize the orthorhombic phase [1], [2]. Fe-FETs employing ferroelectric (FE) HfO 2 in the gate stack attract tremendous attention due to its CMOS compatible process, long retention, and fast read/write speed [3]- [15].…”

“…Ferroelectric/dielectric (FE/DE) stack are commonly used in Fe-FETs because it is critical to realize high-quality interface using interfacial layer as an ultrathin DE in metal-oxide-semiconductor (MOS) type transistors although atomic layer deposited FE HfO 2 is easy to integrate on different semiconductor channels. It was pointed out that the FE/DE stack cannot be simply understood using continuous displacement field condition at FE/DE interface [9], [11], [15], [16]. The reason is that dielectric materials such as SiO 2 or Al 2 O 3 cannot support such high charge density below their breakdown field.…”

“…The reason is that dielectric materials such as SiO 2 or Al 2 O 3 cannot support such high charge density below their breakdown field. Therefore, the interfacial charge at FE/DE interface and leakage-assist polarization switching must be considered for charge balance [15].…”