Electronic states and electric properties under device operation

2014 Fiscal Year Final Research Report

• Project/Area Number: 23560033
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Thin film/Surface and interfacial physical properties
• Research Institution: National Institute for Materials Science
• Principal Investigator: YAMASHITA Yoshiyuki 独立行政法人物質・材料研究機構, ナノエレクトロニクス材料ユニット, MANA研究者 (00302638)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 光電子分光 / オペランド / その場観測 / 高誘電体 / 抵抗変化メモリ

Outline of Final Research Achievements

We employed hard x-ray photoelectron spectroscopy in operating devices. For a Pt gate metal/high-k gate stack structure, we have found that a potential gradient was formed at the Pt/HfO2 interface. Oxide layer formed at the Pt/HfO2 interface is the origin of the potential gradient
For the SiON/Si interface, the interface state density increased with the nitrogen concentration in the oxide, but the spectral shape was independent of the nitrogen concentration. NO species at the SiON/Si interface increase induced inhomogeneous interface sites. The number of inhomogeneous interface sites is proportional to the interface state density. For resistance switching memory, oxygen and Hf atoms in the Pt/HfO2/Pt structure migrate to the top electrode under bias, forming Pt-O bond and Hf-Pt bond at the Pt/HfO2 interface, which could induce resistance switching behavior in this system.

Free Research Field

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