Charge transport in amorphous Hf0.5Zr0.5O2

Abstract

In this study, we demonstrated experimentally and theoretically that the charge transport mechanism in amorphous Hf0.5Zr0.5O2 is phonon-assisted tunneling between traps like in HfO2 and ZrO2. The thermal trap energy of 1.25 eV and optical trap energy of 2.5 eV in Hf0.5Zr0.5O2 were determined based on comparison of experimental data on transport with different theories of charge transfer in dielectrics. A hypothesis that oxygen vacancies are responsible for the charge transport in Hf0.5Zr0.5O2 was discussed.

Metal Nitride Electrode Stress and Chemistry Effects on Phase and Polarization Response in Ferroelectric Hf0.5Zr0.5O2 Thin Films

“…[65,66] While direct examination of defect concentrations in HZO thin films has proven experimentally difficult, leakage current measurements have been utilized to estimate these quantities. [34,67,68] Larger leakage currents have been attributed to higher oxygen point defect concentrations that enable current to flow via compensating electrons and trap-assisted tunneling where the oxygen vacancies serve as traps. Leakage current measurements were thus made on each of the films in both series and are shown in Figure S7 of the Supporting Information.…”

Charge transport mechanism in dielectrics: drift and diffusion of trapped charge carriers

“…neighbouring traps. Recently, it has been shown, that the PATENT model adequately describes the current in high-κ dielectrics 30,[33][34][35] . An energy diagram of the electron tunnelling from a phonon-coupled trap to the other one at a distance of a in an external electric field is shown in Fig.…”

Memtransistors Based on Nanopatterned Graphene Ferroelectric Field-Effect Transistors

“…The bandgap opening in graphene is one of the reasons why we used HfZrO as a substrate for graphene transfer, the other being the very low roughness of HfZrO deposited by ALD, which is around 0.2–0.3 nm [ 19 ]. This is much smaller than the corresponding parameter of SiO 2 , which ranges between 1 and 3 nm depending on the deposition technique [ 19 ], and comparable with that of h-BN, which is about 0.4–0.6 nm [ 20 ].…”

“…All devices were measured at room temperature. The influence of the charge traps at the graphene/HfZrO interface can degrade transistor performance [ 20 ]. However, it was shown that HfZrO-based transistors have charge traps with low relaxation times, which do not influence the transistor performance at room temperature.…”