300-mm Wafer-Scale Deposition of Ferroelectric HfZrO₂ for High Electrical Performance with Back-End-Of-Line Compatible Conditions

Atomic layer deposition (ALD) of hafnium oxide and zirconium oxide has been extensively studied to replace SiO₂ as dielectrics in complementary metal oxide semiconductor (CMOS) technology [1]. Since the discovery of ferroelectricity in Hafnia-based oxides in 2011 [2], there has been growing interest in developing an ALD process to achieve good ferroelectrics within the required thermal budget for back-end-of-line CMOS. This work will discuss the advantages of using ALD precursors with wide ALD windows for achieving high-quality ferroelectric HfZrO₂ films. The crystallinity of the as-deposited films can be tuned to reach the desired electrical performance by adjusting the substrate temperature within the ALD windows. A 300-mm wafer-scale deposition of HfZrO₂ with excellent uniformity across the wafer is demonstrated. The role of different underlying layers for the growth of HfZrO₂ is also discussed. Different metals with a wide range of thicknesses are found to have an impact on the nucleation of the ligands at the surface, which affects the growth per cycle and the leakage of the films. We anticipate our results will broaden the understanding of the ALD process of ferroelectric hafnia-based oxides and bring the technology closer to manufacturing.