Fred Stevie lectures

• SIMS Depth Profiling Outline
  -Rationale for SIMS depth profiling: high sensitivity and good depth resolution
  -Parameter choices – How does one select appropriate parameters for depth profiling?
  -Secondary ion yields – variation of yield for primary beam and element
  -Choice of species – positive or negative ion, atomic or molecular ion
  -Static versus dynamic sputtering – review sputtering process
  -Sputtering rate – dependence on primary beam, specimen material, primary ion current and raster size
  -Raster and gate – basis of depth profiling to obtain good depth resolution
  -Count rate saturation – concept of instantaneous counts
  -Crater measurement – use of stylus profilometer, typical parameters and accuracy
  -Depth profile characteristics – dynamic range, detection limit
  -Quantification – procedure to obtain relative sensitivity factor using ion implantation; creation and use of secondary standards
  -Detection Limit – methods to obtain best sensitivity
  -High mass resolution – calculation of mass interferences
  -Voltage offset – understanding and use of secondary ion energy distribution
  -Small area analysis – detection limit versus analyzed area; design of dedicated analysis areas
  -Depth resolution – lower energy, larger angle of incidence from normal, larger probe ion
  -Ion beam induced roughening – dependence on primary species and incidence angle
  -Insulators – use of charge neutralization; approaches for positive and negative secondary ions
  -Analysis approach – depth profile, mass spectra, additional depth profiles

• Instrument Session – Analyses on CAMECA Ultra-  Oxygen primary beam analysis

1. Raster vs gate optimization
Sample: ion implant of BF₂ in Si analyzed at various raster sizes
(30µm dia detected with 200, 100, 50µm raster)
Show count rate saturation

2. Analysis approach
Layer sample: TaSi₂ on polycrystalline Si on SiO₂ on Si
Depth profile, mass spectrum, voltage offset mass spectrum, additional profile

3. Depth resolution
Sample: multiquantum well or multiple spike
Analyze at high and low energy to show improvement in depth resolution

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