1. Atomic layer deposition of Ta-doped SnO2 films with enhanced dopant distribution for thermally stable capacitor electrode applications.
- Author
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Cho, Cheol Jin, Pyeon, Jung Joon, Hwang, Cheol Seong, Kim, Jin-Sang, and Kim, Seong Keun
- Subjects
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ATOMIC layer deposition , *THIN films , *CAPACITORS , *DOPING agents (Chemistry) , *ELECTRODES - Abstract
Atomic layer deposition (ALD) on Ta-doped SnO 2 thin films is proposed as a methodology for the fabrication of capacitor electrodes, for application in dynamic random-access memories (DRAMs). In ALD of doped materials, dopant concentration gradients inevitably occur due to the cyclic process-based characteristics of ALD. In this study, the dopant distribution improves drastically by the decrease in the growth per cycle of TaO x ALD. The modified ALD recipe exploits the low reactivity between Ta and Sn precursors to facilitate a reduction in the growth per cycle. The Ta-doped SnO 2 films grown based on this modified ALD recipe exhibit improved crystallinity and conductivity. The ALD process yields excellent conformality of the Ta-doped SnO 2 film over a hole structure with a high aspect ratio of ~10, both in terms of physical thickness and composition. Additionally, the Ta-doped SnO 2 films serve as a template for the overgrowing dielectric TiO 2 film, which induces the formation of a high-temperature phase with a high dielectric constant, rutile TiO 2 , and exhibit excellent thermal stability even after annealing at 400 °C in forming gas atmosphere. These findings demonstrate that the proposed methodology for the growth of Ta-doped SnO 2 can facilitate the fabrication of capacitor electrodes for application in DRAMs. Unlabelled Image • A new ALD process of Ta-doped SnO 2 films is demonstrated. • Potential applications include use as reduction-resistant capacitor electrode. • Dopant distribution improves by decrease in the growth per cycle of TaO x ALD. • Films reveal ease of formation of high-k rutile TiO 2 and excellent thermal stability. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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