Resistive switching in Pt/TiO 2 /Pt

Recently, the resistive switching behavior in TiO2 has drawn attention due to its application to resistive random access memory (RRAM) devices. TiO2 shows characteristic non-volatile resistive switching behavior, i.e. reversible switching between a high resistance state (HRS) and a low resistance state (LRS). Both unipolar resistive switching (URS) and bipolar resistive switching (BRS) are found to be observed in TiO2 depending on the compliance current for the electroforming. In this thesis the characteristic current-voltage (I-V) hysteresis in three different states of TiO2, pristine, URS-activated, and BRS-activated states, was investigated and understood in terms of the migration of oxygen vacancies in TiO2. The I-V hysteresis of pristine TiO2 was found to show volatile behavior. That is, the temporary variation of the resistance took place depending on the applied voltage. However, the I-V hysteresis of URS- and BRS-activated states showed non-volatile resistive switching behavior. Some evidences proving the evolution of oxygen gas during electroforming were obtained from time-of-flight secondary ion mass spectroscopy analysis and the variation of the morphology of switching cells induced by the electroforming. On the assumption that a large number of oxygen vacancies are introduced by the electroforming process, the I-V behavior in electroformed switching cells was simulated with varying the distribution of oxygen vacancies in electroformed TiOx (x<2). The I-V hysteresis undergoing the BRS was simulated with taking into consideration oxygen formation/annihilation reactions at a Pt/TiOx interface. The oxygen-related reactions given as a function of the applied voltage affect the distribution of oxygen vacancies in TiOx, consequently, the Schottky barrier height at the cathode/TiOx interface is influenced by the oxygen vacancy distribution. Therefore, the BRS behavior including the electroforming characteristics could be understood in terms of the oxygen-related electrochemical reactions.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2008

Author dc:creator

• Jeong, Doo Seok

Contributors dc:contributor

• Gottstein, Günter

• info:eu-repo/classification/ddc/004
• Titandioxid
• Informatik
• Resistives Schalten
• bipolares Schalten
• unipolares Schalten
• Resistive switching
• TiO2
• bipolar switching
• unipolar switching

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112789%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50236