Impact of Annealing Ambience on Resistive Switching in Pt/TiO2/Pt Structure

Guobin WEI  Yuta GOTO  Akio OHTA  Katsunori MAKIHARA  Hideki MURAKAMI  Seiichiro HIGASHI  Seiichi MIYAZAKI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E94-C   No.5   pp.699-704
Publication Date: 2011/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.699
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Fundamentals and Applications of Advanced Semiconductor Devices)
Category: 
Keyword: 
ReRAM,  TiO2,  low temperature,  H2 annealing,  charge trapping,  

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Summary: 
Resistive switching of metal-insulator-metal (MIM), consisting of a metal-organic chemical vapour deposition (MOCVD) TiO2 layer sandwiched between Pt electrodes, has been measured systematically before and after thermal annealing in different ambiences. With H2 annealing at 400, the current level in the high-resistive state (HRS) significantly decreased while little change in the low-resistive state (LRS) was observed. As a result, the switching ratio over 7 orders of magnitude at the current level was obtained. From the analysis of current-voltage (I-V) characteristics in HRS and LRS, we found that the LRS was characterized with an ohmic conduction, while in the HRS after H2 annealing, charge trapping became significant as a result of a significant decrease in the current level. In a separate experiment, a partial reduction in TiO2 was detected using high-resolution X-ray photoelectron spectroscopy (XPS) after resistant-state switching from HRS to LRS by using a Hg probe as a top electrode, which is associated with filament formation.