Achieving High Dielectric Constants in Tetragonal Single‐Phase ZrHfO2 Thin Films through the Atomic Layer Deposition Process Using a Mixed Precursor

Herein, the deposition of homogeneous Zr x Hf (1− x ) O 2 ( x < 1) thin films for dynamic random‐access memory (DRAM) capacitor dielectric layers by atomic layer deposition (ALD) using a mixed precursor mixture of two precursors is investigated. ZrO 2 ‐ and HfO 2 ‐based thin films are widely used as capacitor dielectric layers because of their high dielectric constant ( k ) values and low leakage current properties. Herein, particularly, films with mixed structures of ZrO 2 /HfO 2 are investigated because ZrO 2 supports the growth of HfO 2 in the tetragonal phase. However, the mixed structures deposited by ALD remain inhomogeneous even after the annealing process. The inhomogeneity results in part of the HfO 2 remaining in the monoclinic phase, which reduces the k value. Herein, the formation of homogeneous tetragonal‐phase Zr x Hf 1− x O 2 using a mixed precursor consisting of CpZr and CpHf precursors is investigated. The formation of the tetragonal phase in the Zr x Hf (1− x ) O 2 thin films is determined through chemical and structural analysis. The variation of the electrical properties with the Zr/Hf concentration ratio is investigated. The electrical properties are enhanced compared to laminated ZrO 2 /HfO 2 and single thin films.