Characterization of local electrical properties of gate dielectrics by conductive atomic force microscopy

Research output: Contribution to journalArticle

Abstract

A conducting atomic force microscopy (C-AFM) in ultrahigh vacuum is used to directly observe the evolution of leakage path in HfO 2 gate dielectrics. Thanks to the UHV environment, reproducible results for both positive and negative tip biases are obtained without material formation on the surface, which has been a problem for atmospheric C-AFM. It is found that the density of leakage spots increases exponentially as a function of tip bias and that it is a large factor for leakage current increase. It is also found that these local leakage paths in HfO 2 films annihilate after applying a reverse tip bias. This process seems to be related to the initial stage of the forming process of resistive switching materials. The fact that these paths annihilate by a very small reverse bias suggests that this behavior is caused by local reduction and oxidation in the HfO 2 layer.

Original languageEnglish
Pages (from-to)420-426
Number of pages7
JournalJournal of the Vacuum Society of Japan
Volume54
Issue number7-8
Publication statusPublished - 2011

Fingerprint

Gate dielectrics
Atomic force microscopy
Electric properties
leakage
electrical properties
atomic force microscopy
Ultrahigh vacuum
Leakage currents
conduction
Oxidation
ultrahigh vacuum
oxidation

ASJC Scopus subject areas

  • Spectroscopy
  • Materials Science(all)
  • Instrumentation
  • Surfaces and Interfaces

Cite this

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title = "Characterization of local electrical properties of gate dielectrics by conductive atomic force microscopy",
abstract = "A conducting atomic force microscopy (C-AFM) in ultrahigh vacuum is used to directly observe the evolution of leakage path in HfO 2 gate dielectrics. Thanks to the UHV environment, reproducible results for both positive and negative tip biases are obtained without material formation on the surface, which has been a problem for atmospheric C-AFM. It is found that the density of leakage spots increases exponentially as a function of tip bias and that it is a large factor for leakage current increase. It is also found that these local leakage paths in HfO 2 films annihilate after applying a reverse tip bias. This process seems to be related to the initial stage of the forming process of resistive switching materials. The fact that these paths annihilate by a very small reverse bias suggests that this behavior is caused by local reduction and oxidation in the HfO 2 layer.",
author = "Kentaro Kyuno",
year = "2011",
language = "English",
volume = "54",
pages = "420--426",
journal = "Journal of the Vacuum Society of Japan",
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AU - Kyuno, Kentaro

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AB - A conducting atomic force microscopy (C-AFM) in ultrahigh vacuum is used to directly observe the evolution of leakage path in HfO 2 gate dielectrics. Thanks to the UHV environment, reproducible results for both positive and negative tip biases are obtained without material formation on the surface, which has been a problem for atmospheric C-AFM. It is found that the density of leakage spots increases exponentially as a function of tip bias and that it is a large factor for leakage current increase. It is also found that these local leakage paths in HfO 2 films annihilate after applying a reverse tip bias. This process seems to be related to the initial stage of the forming process of resistive switching materials. The fact that these paths annihilate by a very small reverse bias suggests that this behavior is caused by local reduction and oxidation in the HfO 2 layer.

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