Atomic Layer Deposition of Epitaxial Ferroelectric Hf_0.5Zr_0.5O₂ Thin Films

Abstract

The groundbreaking discovery of unconventional ferroelectricity in HfO2 opens exciting prospects for next‐generation memory devices. However, the practical implementation, particularly its epitaxial stabilization and a clearer understanding of its intrinsic ferroelectricity has been a significant challenge. The study arouses the potential importance of atomic layer deposition (ALD) for mass production in modern industries, demonstrating its proficiency in achieving epitaxial growth of ferroelectric Hf0.5Zr0.5O2 (HZO) thin films on Yttria‐stabilized zirconia (YSZ) substrates. Moreover, with distinct ferroelectric switching currents, the work reveals the ferroelectric characteristics of epitaxial HZO thin films deposited through ALD on YSZ‐buffered Si substrates, which aligns well with CMOS technology. Overall, the results pave the way for a scalable synthesis system for ferroelectric HfO2‐based materials, hinting at a bright future for low‐temperature epitaxial nanoelectronics.

Symmetry Engineering of Epitaxial Hf0.5Zr0.5O2 Ultrathin Films

“…Reversible spontaneous polarization, which characterizes ferroelectricity with breaking of the inversion symmetry, is crucial for various applications in memory devices, microelectronics, and spintronics. − Recently, HfO 2 -based binary oxides have been discovered to exhibit robust ferroelectricity, in which spontaneous polarization increases as the dimension decreases, especially in ultrathin limits (below 10 nm). − Because HfO 2 -based materials are CMOS-compatible, have simple chemistry, and exhibit low toxicity, they have become appealing and promising candidates for the integration of ferroelectric layers into Si-based semiconductor technologies. − …”