If the composition of a bulk material or a thin layer has to be analyzed, the choice of the analytical technique depends on the information already available at the beginning and on the information which are required (main elements, trace elements, chemical compounds). It is also decidive, if a bulk, surface or layer analysis has to be conducted.
To analyze the composition of a surface, analytical methods are required, which are characterized by a low depth of information (< 10 nm). These are for example X-ray Photoelectron Spectroscopy (XPS) or Secondary Ion Mass Spectrometry (TOF-SIMS).
Moreover ATR-IR, a specific method of infrared spectroscopy, is available. In some instances the SEM/EDS microanalysis can also make contributions, however the depth of information in EDS is already in the range of ~ 1 micron. Nevertheless low voltage imagaging by SEM can allow to visualize the lateral distribution of thin layers on surfaces.
Thin Layer Analysis
Depending on the thickness of the layer to be analyzed different approaches may be applied. For thicker layers (about > 100 nm), an analysis of cross-sections by Scanning Electron Microscopy (SEM) and X-Ray Micro-Area Analysis (EDS) can be done. By this the elemental composition and structure can be evaluated.
The main organic components can be examined by Infrared Spectroscopy (FTIR / ATR-IR) or IR microscopy. For thinner layers specific surface analytical and sputter depth profiling techniques can be used. The Secondary Ion Mass Spectroscopy (TOF-SIMS) is used to identify organic compounds such as polymers, lubricants or Additives.
The X-Ray Photoelectron Spectroscopy (XPS) is suitable for the quantitative analysis of the elemental composition and the bonding states at the surface and in the depth of the layer (sputter depth profiling). Especially for depth profiling of organic compound,s argon cluster sputtering can be used.
A bulk analysis is either carried out by techniques which have a very high depth of information, such as the X-ray fluorescence (XRF), or the material is disintegrated and analised by appropriate procedures as ICP-OES (Inductively Coupled Plasma with Optical Emission Spectroscopy).