High-temperature atomic layer deposition of HfO2 film with low impurity using a novel Hf precursor

Abstract

We compared the physicochemical and electrical properties of HfO₂ thin films grown at a high temperature of 350 °C using tris(dimethylamido)cyclopentadienylhafnium (CpHf(NMe₂)₃) and a novel Hf precursor, tris(dimethylamido)isopropenylcyclopentadienylhafnium (FuHf(NMe₂)₃). Experimental results indicate that the FuHf(NMe₂)₃ precursor exhibits superior thermal stability compared to the CpHf(NMe₂)₃ precursor, making it highly advantageous for high-temperature processes. Accordingly, the ALD temperature window range of the film grown using FuHf(NMe₂)₃ is higher by approximately 50 °C. Due to the enhanced thermal stability, the HfO₂ film grown using FuHf(NMe₂)₃ exhibits reduced impurity concentration compared to the film grown using CpHf(NMe₂)₃, resulting in increased physical density. Consequently, the improved physicochemical properties of HfO₂ films grown using FuHf(NMe₂)₃ enhanced their electrical characteristics including dielectric constant, leakage current, and dielectric breakdown properties.