Temperature-Dependent Physical and Memory Characteristics of Atomic-Layer-Deposited RuOx Metal Nanocrystal Capacitors
Resource
Journal of Nanomaterials, 2011, 810879
Journal
Journal of Nanomaterials
Pages
1
Date Issued
2011
Date
2011
Author(s)
Abstract
Physical and memory characteristics of the atomic-layer-depositedRuOxmetal nanocrystal capacitors in an n-Si/SiO 2 /HfO 2 /RuOx/Al 2 O 3 /Pt structure with different postdeposition annealing temperatures from 850–1000 ° C have been investigated. TheRuOxmetal nanocrystals with an average diameter of 7 nm and a highdensity of 0.7 × 10 12 /cm 2 are observed by high-resolution transmission electron microscopy after a postdeposition annealing temperature at 1000 ° C. The density ofRuOxnanocrystal is decreased (slightly) by increasing the annealing temperatures, due to agglomeration of multiple nanocrystals. The RuO 3 nanocrystals and Hf-silicate layer at the SiO 2 /HfO 2 interface are confirmed by X-ray photoelectron spectroscopy. For post-deposition annealing temperature of 1000 ° C, the memory capacitors with a small equivalent oxide thickness of ~9 nm possess a large hysteresis memory window of >5 V at a small sweeping gate voltage of ±5 V. A promising memory window under a small sweeping gate voltage of ~3 V is also observed due to charge trapping in theRuOxmetal nanocrystals. The program/erase mechanism is modified Fowler-Nordheim (F-N) tunneling of the electrons and holes from Si substrate. The electrons and holes are trapped in theRuOxnanocrystals. Excellent program/erase endurance of 10 6 cycles and a large memory window of 4.3 V with a small charge loss of ~23% at 85 ° C are observed after 10 years of data retention time, due to the deep-level traps in theRuOxnanocrystals. The memory structure is very promising for future nanoscale nonvolatile memory applications.
Type
journal article
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