Direct comparison of ferroelectric properties in Hf0.5Zr0.5O2 between thermal and plasma-enhanced atomic layer deposition

Since the discovery of ferroelectricity in doped/alloyed HfO2and ZrO2thin film, many device engineers have been attracted to its sustainable ferroelectricity at the thickness of a few nanometer. While most of the previous studies have mainly focused on the ferroelectric properties of the thermally atomic layer deposited (THALD) Hf0.5Zr0.5O2(HZO), the plasma-enhanced ALD (PEALD) HZO has not been attained much attention. In this work, a direct comparison between the two types of HZO thin films is carried out, where we found that a tradeoff exists between these two fabrication methods. While the THALD HZO was able to maintain a higher cycling endurance, the PEALD HZO showed more stable characteristics over the cycling with reduced wake-up and fatigue effects, in addition to better tolerance against breakdown under high electric field. Furthermore, the PEALD HZO could be crystallized with post deposition annealing at 350oC, which is of great interests for the back-end-of-line compatibility with silicon fabrication processes.