Improved Properties of the Atomic Layer Deposited Ru Electrode for Dynamic Random-Access Memory Capacitor Using Discrete Feeding Method
| Autor: | Woojin Jeon, Dae Seon Kwon, Dong Gun Kim, Haengha Seo, Cheol Seong Hwang, Junil Lim, Tae Kyun Kim |
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| Rok vydání: | 2021 |
| Předmět: |
Dynamic random-access memory
Materials science Analytical chemistry Equivalent oxide thickness 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Atomic layer deposition Crystallinity law Phase (matter) Electrode General Materials Science Thin film 0210 nano-technology Layer (electronics) |
| Zdroj: | ACS Applied Materials & Interfaces. 13:23915-23927 |
| ISSN: | 1944-8252 1944-8244 |
| Popis: | Ruthenium (Ru) thin films deposited via atomic layer deposition (ALD) with a normal sequence and discrete feeding method (DFM) and their performance as a bottom electrode of dynamic random-access memory (DRAM) capacitors were compared. The DFM-ALD was performed by dividing the Ru feeding and purge steps of the conventional ALD process into four steps (shorter feeding time + purge time). The surface morphology of the Ru films was improved significantly with the DFM-ALD, and the preferred orientation of the Ru films was changed from relatively random to a -oriented direction. Under the DFM-ALD condition, the higher susceptibility of oxygen atoms to the Ru electrode resulted in a higher proportion of the RuO2 formation on the Ru film surface during the subsequent TiO2 ALD process. This higher RuO2 portion leads to higher crystallinity of the local-epitaxially grown TiO2 films with a rutile phase. Such improvement also decreased the interfacial component of equivalent oxide thickness (EOTi) by ∼0.1 nm compared with the cases on sputtered Ru film, which showed an even smoother surface morphology. Consequently, the minimum EOT values when the Ru bottom electrodes deposited via DFM-ALD were adopted were 0.76 and 0.48 nm for TiO2 and Al-doped TiO2 films, respectively, while still satisfying the DRAM leakage current density specification ( |
| Databáze: | OpenAIRE |
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