Ruthenium oxide metal nanocrystal capacitors with high-kappa dielectric tunneling barriers for nanoscale nonvolatile memory device applications
Resource
Microelectronic Engineering, 87(10), 1821-1827
Journal
Microelectronic Engineering
Journal Volume
87
Journal Issue
10
Pages
1821-1827
Date Issued
2010
Date
2010
Author(s)
Das, Atanu
Maikap, S.
Lin, C.-H.
Tzeng, P.-J.
Tien, T.-C.
Wang, T.-Y.
Chang, L.-B.
Yang, J.-R.
Abstract
The ruthenium oxide metal nanocrystals embedded in high-κ HfO 2/Al2O3 dielectric tunneling barriers prepared by atomic layer deposition in the n-Si/SiO2/HfO2/ruthenium oxide (RuOx )/Al2O3/Pt memory capacitors with a small equivalent oxide thickness of 8.6 ± 0.5 nm have been investigated. The RuOx metal nanocrystals in a memory capacitor structure observed by high-resolution transmission electron microscopy show a small average diameter of ∼7 nm with high-density of >1.0 × 10 12/cm2 and thickness of ∼3 nm. The ruthenium oxide nanocrystals composed with RuO2 and RuO3 elements are confirmed by X-ray photoelectron spectroscopy. The enhanced memory characteristics such as a large memory window of ΔV ≈ 12.2 V at a sweeping gate voltage of ±10 V and ΔV ≈ 5.2 V at a small sweeping gate voltage of ±5 V, highly uniform and reproducible, a large electron (or hole) storage density of ∼1 × 1013/cm 2, low charge loss of <7% (ΔV ≈ 4.2 V) after 1 × 104 s of retention time are observed due to the formation of RuO x nanocrystals after the annealing treatment and design of the memory structure. The charge storage in the RuOx nanocrystals under a small voltage operation (∼5 V) is due to the modified Fowler-Nordheim tunneling mechanism. This memory structure can be useful for future nanoscale nonvolatile memory device applications. © 2009 Elsevier B.V. All rights reserved.
Type
journal article
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