Effect of Process Temperature on Density and Electrical Characteristics of Hf0.5Zr0.5O2 Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition

Abstract

HfxZr1−xO2 (HZO) thin films have excellent potential for application in various devices, including ferroelectric transistors and semiconductor memories. However, such applications are hindered by the low remanent polarization (Pr) and fatigue endurance of these films. To overcome these limitations, in this study, HZO thin films were fabricated via plasma-enhanced atomic layer deposition (PEALD), and the effects of the deposition and post-annealing temperatures on the density, crystallinity, and electrical properties of the thin films were analyzed. The thin films obtained via PEALD were characterized using cross-sectional transmission electron microscopy images and energy-dispersive spectroscopy analysis. An HZO thin film deposited at 180 °C exhibited the highest o-phase proportion as well as the highest density. By contrast, mixed secondary phases were observed in a thin film deposited at 280 °C. Furthermore, a post-annealing temperature of 600 °C yielded the highest thin film density, and the highest 2Pr value and fatigue endurance were obtained for the film deposited at 180 °C and post-annealed at 600 °C. In addition, we developed three different methods to further enhance the density of the films. Consequently, an enhanced maximum density and exceptional fatigue endurance of 2.5 × 107 cycles were obtained.

Preparation of Remote Plasma Atomic Layer-Deposited HfO2 Thin Films with High Charge Trapping Densities and Their Application in Nonvolatile Memory Devices

“…Under the optimized process conditions reported in our previous studies [27,28], MIS capacitors were fabricated by depositing DP-and RP-HfO 2 thin films on p-Si wafers and developing Pt electrodes. HfO 2 thin films were deposited by splitting the temperature in the range of 200-260 • C, which was considered the process window, and the thickness of the deposited film was determined to be approximately 10 nm by the ellipsometer.…”

Editorial for the Special Issue “Nanoscale Ferroic Materials—Ferroelectric, Piezoelectric, Magnetic, and Multiferroic Materials”

“…Kim et al fabricated Hf 0.5 Zr 0.5 O 2 thin films via plasma-enhanced atomic layer deposition. A high remanent polarization with 2 P r of 38.2 μC/cm 2 and an excellent fatigue endurance of 2.5 × 10 7 cycles were obtained by regulating the deposition temperature, post-annealing temperature and RF plasma discharge time [ 1 ]. Among the studies about Hf x Zr 1-x O 2 , the work in this study showed relatively good remanent polarization and fatigue endurance performances despite being under the lowest deposition temperature.…”