Characteristics of the Hf0.5Zr0.5O2 Thin Films Grown by a Chemical Solution Deposition Method

This paper describes morphological, optical, compositional, and structural characteristics of the Hf0.5Zr0.5O2 (HZO) thin films grown on Si and sapphire substrates by a chemical solution deposition method by spin coating using HfCl4 and ZrCl4 for the starting agents. Clear and smooth HZO thin films of about 20 nm thick were obtained after the spin-coating of the chemical solution followed by a drying process at 150°C and a sintering process at 500-800°C. The compositional ratio of Hf : Zr in the HZO thin films was 1 : 1 in good agreement with the molar ratio of HfCl4 and ZrCl4 in the chemical solution. It was revealed that the HZO thin films were crystallized in orthorhombic structure under the sintering in N2, while monoclinic structure became dominant under the sintering in air.