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

초록

We compared the physicochemical and electrical properties of HfO2 thin films grown at a high temperature of 350 degrees 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 degrees 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.

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