Atomic layer deposition of hafnium silicate thin films using a single source precursor

초록

Atomic layer deposition (ALD) of hafnium silicate (HfSiOx) thin films is demonstrated using a novel single-source precursor that incorporates both hafnium (Hf) and silicon (Si) within a single molecule. This approach provides a direct and well-controlled route to homogeneous Hf-Si mixing at the atomic scale, eliminating the need for multiple precursors or additional mixing steps. The resulting films were comprehensively characterized to evaluate film thickness, composition, and density using spectroscopic ellipsometry, X-ray photoelectron spectroscopy, and X-ray reflectivity, respectively, along with electrical measurements performed on metal-oxide-semiconductor capacitor structures. The extracted electrical properties, including a dielectric constant of 9.1, a capacitance equivalent thickness of 2.9 nm, and suppressed leakage current, indicate the formation of high-quality HfSiOx films and demonstrate the viability of this simplified process. Furthermore, a surface reaction mechanism involving dual adsorption pathways of the precursor is proposed and strongly supported by experimental evidence. This work establishes a simplified and effective ALD strategy for fabricating high-performance HfSiOx dielectrics, providing a viable route toward their integration in next-generation CMOS devices.

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