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

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 (P-r) 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 degrees 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 degrees C. Furthermore, a post-annealing temperature of 600 degrees C yielded the highest thin film density, and the highest 2P(r) value and fatigue endurance were obtained for the film deposited at 180 degrees C and post-annealed at 600 degrees 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 x 10(7) cycles were obtained.

Automated summary

In this study, HZO thin films were fabricated via plasma-enhanced atomic layer deposition, and the effects of deposition and post-annealing temperatures on the films' properties were analyzed. The results showed that specific deposition and post-annealing temperatures could improve the density and fatigue endurance of the films.