Study of SiO2 Interfacial Layer Growth during Fabrication Process of Ferroelectric HfxZr1−XO2-Based Metal-Ferroelectric Semiconductor

Abstract

We studied a SiO2 interfacial layer (SiO2-IL) growth between a ferroelectric HfxZr1−xO2 (HZO) film, which fabricated by atomic layer deposition (ALD) using a Hf/Zr cocktail precursor, and p-type Si substrate during the metal-ferroelectric-semiconductor (MFS) fabrication. For the annealing process, two types of a post-deposition annealing (PDA) and post-metallization annealing (PMA) were employed before and after the fabrication of the TiN top-electrodes, respectively. An ultra-thin SiO2-IL of one or two monolayers at the HZO/Si interface was achieved using a 300°C fabrication process of ALD, and PDA or PMA. In contrast, PDA and PMA processes at ≥ 400°C led to an unexpected SiO2-IL formation, which increased with the annealing temperature, regardless of the formation of TiN top-electrodes. Therefore, we found that a suppressed SiO2-IL of HZO-based MFS structures can be obtained using the 300°C fabrication process.