Impact of electrically formed interfacial layer and improved memory characteristics of IrOx-high-κx-W structures containing AlOx, GdOx, HfOx, and TaOx switching materialsReport as inadecuate




Impact of electrically formed interfacial layer and improved memory characteristics of IrOx-high-κx-W structures containing AlOx, GdOx, HfOx, and TaOx switching materials - Download this document for free, or read online. Document in PDF available to download.

Nanoscale Research Letters

, 8:379

First Online: 06 September 2013Received: 09 July 2013Accepted: 15 August 2013

Abstract

Improved switching characteristics were obtained from high-κ oxides AlOx, GdOx, HfOx, and TaOx in IrOx-high-κx-W structures because of a layer that formed at the IrOx-high-κx interface under external positive bias. The surface roughness and morphology of the bottom electrode in these devices were observed by atomic force microscopy. Device size was investigated using high-resolution transmission electron microscopy. More than 100 repeatable consecutive switching cycles were observed for positive-formatted memory devices compared with that of the negative-formatted devices only five unstable cycles because it contained an electrically formed interfacial layer that controlled ‘SET-RESET’ current overshoot. This phenomenon was independent of the switching material in the device. The electrically formed oxygen-rich interfacial layer at the IrOx-high-κx interface improved switching in both via-hole and cross-point structures. The switching mechanism was attributed to filamentary conduction and oxygen ion migration. Using the positive-formatted design approach, cross-point memory in an IrOx-AlOx-W structure was fabricated. This cross-point memory exhibited forming-free, uniform switching for >1,000 consecutive dc cycles with a small voltage-current operation of ±2 V-200 μA and high yield of >95% switchable with a large resistance ratio of >100. These properties make this cross-point memory particularly promising for high-density applications. Furthermore, this memory device also showed multilevel capability with a switching current as low as 10 μA and a RESET current of 137 μA, good pulse read endurance of each level >10 cycles, and data retention of >10 s at a low current compliance of 50 μA at 85°C. Our improvement of the switching characteristics of this resistive memory device will aid in the design of memory stacks for practical applications.

KeywordsResistive switching W-TaOx Ti nanolayer Oxygen ion migration Nanofilament Electronic supplementary materialThe online version of this article doi:10.1186-1556-276X-8-379 contains supplementary material, which is available to authorized users.

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Author: Amit Prakash - Siddheswar Maikap - Writam Banerjee - Debanjan Jana - Chao-Sung Lai

Source: https://link.springer.com/







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