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

Research output: Contribution to journalReview article

Abstract

A conducting atomic force microscopy (C-AFM) in ultrahigh vacuum is used to directly observe the evolution of leakage path in HfO2 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 HfO2 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 HfO2 layer.

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

ASJC Scopus subject areas

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

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