Modelling of scanning probe microscopy

R. J. Cobley, K. Kalna and Olga Krychenkova.

As the active regions of electronic materials and devices reduce in size to the nanoscale, the analysis tools need to characterise those with a spatial resolution in the same length scale. Scanning probe microscopy is one such technique and can be used to make surface electronic, morphological, optical, chemical and magnetic measurements down to the atomic scale. Unlike most electron microscopy techniques, scanning probe microscopy can be applied to biased devices under operation. The main limitation of the method is that with all scanning probe microscopy techniques the probe can interact electrostatically and physically with the sample, changing the measured properties of the device under test. We model scanning probe microscopy within TCAD Silvaco Atlas software using 2D finite element device simulations which have the following capabilities:

  • self-consistent physically based modelling
  • direct quantum tunnelling model using Price and Radcliffe formalism
  • arbitrary realistic tip shapes
  • full device transport models for scanning probe miscroscopy on devices
  • realistic interaction of the probe and sample using a tip-induced band-bending
  • image force correction can be included in the simulations
  • modelling of the spectra obtained from scanning probe miscroscopy on powered devices
  • including the effect of surface states