Conventional and back-side focused ion beam milling for off-axis electron holography of electrostatic potentials in transistors

Rafal E. Dunin-Borkowski, Simon B. Newcomb, Takeshi Kasama, Martha McCartney, Matthew Weyland, Paul A. Midgley

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Off-axis electron holography is used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope (TEM) using focused ion beam (FIB) milling from the substrate side of the semiconductor device. The measured electrostatic potential is compared with results obtained from TEM specimens prepared using the more conventional 'trench' FIB geometry. The use of carbon coating to remove specimen charging effects, which result in electrostatic fringing fields outside 'trench' specimens, is demonstrated. Such fringing fields are not observed after milling from the substrate side of the device. Analysis of the measured holographic phase images suggests that the electrically inactive layer on the surface of each FIB-milled specimen typically has a thickness of 100 nm.

Original languageEnglish (US)
Pages (from-to)67-81
Number of pages15
JournalUltramicroscopy
Volume103
Issue number1
DOIs
StatePublished - Apr 1 2005

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Keywords

  • Back-side milling
  • Charging
  • Dopant contrast
  • Electrostatic potential
  • Focused ion beam milling
  • Off-axis electron holography
  • Specimen preparation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Instrumentation

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