Stabilizing SrVO₃ bottom electrodes for high-k SrTiO₃ integration via La-doped STO passivation and O₃-reduced atomic layer deposition

The increasing demand for higher capacitance densities in dynamic random-access memory (DRAM) has necessitated the integration of high-k dielectric materials. SrTiO3 (STO) has emerged as a promising candidate owing to its high dielectric constant of over 100 in thin-film form. Selection of bottom electrode materials with superior lattice matching with STO is crucial to achieve a high dielectric constant for STO. This study evaluates the potential of using SrVO3 (SVO) electrodes with atomic layer deposition (ALD)-grown STO for DRAM and addresses the challenges associated with SVO stability during the ALD STO process. The results indicate that applying La:STO oxygen-blocking layers effectively mitigates SVO degradation during the ALD process. Furthermore, reducing the O3 concentration during ALD enabled the successful integration of high-quality STO on SVO with a bulk dielectric constant of 175 and exceptionally well-maintained interfacial properties. The findings validate SVO as a promising bottom electrode for ALD STO dielectric films in next-generation DRAM, demonstrating its potential to achieve increased capacitance density and reduced leakage currents. The advancement of dynamic random-access memory (DRAM) technology necessitates the development of capacitor dielectrics with higher dielectric constants. Traditional high-k materials like Al2O3, ZrO2, and HfO2 have reached their limits, prompting the exploration of ternary oxides such as SrTiO3 (STO) for next-generation DRAM capacitors. This study investigates the use of SrVO3 (SVO) as a bottom electrode for atomic layer deposition (ALD) of STO films, addressing the challenge of SVO's oxidation during the ALD process. Researchers employed a La-doped STO passivation layer and optimized ALD conditions by reducing O3 concentration to protect SVO from degradation. Results showed that the SVO/STO capacitors achieved a bulk dielectric constant of 175, demonstrating excellent dielectric properties. This research highlights the potential of SVO as an electrode material for DRAM capacitors, suggesting future directions in optimizing interface engineering and exploring alternative electrode materials.