XPS: X-ray Photoelectron Spectroscopy
(ESCA: Electron Spectroscopy for Chemical Analysis)
Principle of measurement
When X-rays are irradiated to a sample surface, the inner-shell electrons of atoms
are excited, and photoelectrons are discharged from the sample surface. This technique
identifies the elements existing on the sample surface and analyzes their chemical
bonding conditions detecting the kinetic energy of the discharged photoelectrons.
Kinetic energy of discharged photoelectrons
Intrinsic energy of X-rays (known)
Binding energy of orbital electrons (known)
Work function inherent in equipment (known)
Major analytical applications for semiconductor materials
1.Analysis of outermost surface composition and analysis
of bonding condition
Information on the component elements on a substance surface and their chemical
bonding conditions can be obtained by measurement on the surface of the substance
(approx. 10 nm).
Analysis of particles adhering to substrate surface
Analysis of oxidation conditions on metallic thin films
Calculation of natural oxide film thickness
Analysis of CF deposited films
Evaluation of corrosion of metallic materials
Measurement of magnetic disk lubricating film thickness
Analysis of various reaction products
Evaluation of modification of surfaces of films and
Wide scanning measurement
2. Analysis by angle resolving method
In-depth information can be obtained non-destructively by
changing the photoelectron taking angle. The sensitivity on the polar surface
can be improved by considerably reducing the photoelectron taking angle.
Change in composition and bonding conditions on outermost
layer (10 nm)
Analysis of physical adsorbed species
Narrow scanning measurement
3. In-depth analysis (depth profiling)
the above technique with sputtering by ion (AR or Xe) irradiation enables to
obtain information on the composition, changes in bonding conditions and diffusion
conditions from the surface to the depth.
Analysis of composition of various thin films
Evaluation of thin film thickness
Investigation of interfaces of multi-layer films
4. Analysis in linear direction (line profiling)
The analysis point is automatically shifted linearly, and
the distribution between any two points on the sample surface can be determined.
This technique can be applied to surface analysis (mapping).
Examination of distribution of lubricating film thickness
on magnetic disk
Examination of distribution of surface contamination
Examination of distribution of oxidization level on