Investigating potential use of TiO2 as conductive-like layer in DRAM capacitors

초록

As the scaling of dynamic random-access memory (DRAM) devices continues, the formation of an interfacial dead layer between the high-k dielectric and the metal electrode is the main cause of the deterioration of electrical characteristics. In this study, we propose a strategy to improve the equivalent oxide thickness (EOT) using a TiN film treated with trimethylaluminum (TMA) as an interfacial layer to provide conductive-like properties. The TMA-treated TiO₂ exhibited conductive-like properties with a decrease in resistivity owing to an increase in the oxygen-vacancy concentration, as confirmed by angle-resolved X-ray photoelectron spectroscopy and electrical-property measurements. When the TMA-treated TiO₂ film was inserted between TiN and ZrO₂, the formation of an interfacial dead layer was effectively suppressed, resulting in an increase in the dielectric constant, a reduction in the leakage current, and an improvement in the EOT without a change in the ZrO₂ crystal phase. This study demonstrates that interface control using conductive-like TiO₂ films can be an effective strategy in high-k/metal stacks and suggests the possibility of further scaling the EOT of DRAM capacitors. © 2025 Elsevier B.V., All rights reserved.

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