Nanoelectrical Characterization of Thin Insulating Films with AFM

Thin insulating films are used as dielectric layers in electronics and for lightweight insulation on cables. In these applications, a critical performance measure is the dielectric breakdown strength of the films. Macroscale Time-Dependent Dielectric Breakdown (TDDB) measurements are most commonly used for characterization, but atomic force microscopy enables a more detailed understanding of how microscale defects affect film properties.

This application note describes two techniques for the characterization of these insulating films. First, conventional topographic imaging with atomic force microscopy (AFM) is combined with Conductive AFM (CAFM) to map the presence of microscale defects in the film and determine if current leakage occurs at those defects. Second, a lesser-known technique called Nanoscale Time-Dependent Dielectric Breakdown (nanoTDDB) is used to make a nanoscale analogue of the macroscale TDDB measurements. These nanoTDDB measurements help provide a better understanding of how film breakdown occurs at the nano- and microscale.

This application note describes:

• Overview of the motivation for developing improved dielectric thin films
• Comparison of dielectric films deposited with different plasma vapor deposition (PVD) techniques
• Mapping microscale defects with AFM and measuring current leakage
• Introduction of the Nanoscale Time-Dependent Dielectric Breakdown (nanoTDDB) technique, which complements conventional macroscale TDDB measurements

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