Silicon • Metalloid

Primary XPS region: Si2p
Overlapping regions: N/A
Binding energies of common chemical states:

Chemical stateBinding energy Si2p
Si element99.4 eV
Si3N4101.7 eV
ZrSiO4102 eV
Organic Si~102 eV
Aluminusilicate102.7 eV
SiO2103.5 eV

Silicates and nitride referenced to C1s at 284.8eV.


Experimental information

  • In the presence of high lanthanum concentrations, acquire Si2s as well as (or instead of) the Si2p peak.


Interpretation of XPS spectra

  • Si2p peak has closely-spaced spin-orbit components (Δ=0.63eV).
    • It normally only needs to be considered for elemental Si.
      • Splitting may be ignored for Si2p peaks from silicon compounds.
  • Observed as either two distinct, symmetric components (at low pass energy) or as single, asymmetric peak (at higher pass energy).
  • Observed spectral resolution of spin-orbit components is affected by the crystallinity/amorphous character of the elemental silicon.
    • The more crystalline, the better resolution of spin-orbit components.
    • The more amorphous (caused by Ar+ sputtering, for example), the worse resolution of spin-orbit components.




General comments

  • Silicon is the basis of semiconductor manufacture and silicon wafers are the most common substrate.
  • Silicon will usually have a native oxide of a few angstroms thickness although the exact thickness will depend upon the nature of the final surface cleaning.
    • The relative intensities of the oxide and elemental peaks will also change with oxide thickness.
    • This effect allows XPS to measure the thickness of Si oxide films.
  • H-passivated or H-terminated silicon has a treatment which replaces surface Si-Si dangling bonds with Si-H bonds. These prevent the formation of a surface oxide layer.
  • Organic silicon compounds are widely used as lubricants and release agents especially in the preparation of polymer materials.
    • Traces of silicon may therefore be observed on polymer surfaces.
    • Can also be present on other materials which may have been in contact with other surfaces, e.g., polythene bags.
    • The spectrum below is from typical “as received” industrial PET film and shows Si contamination (siloxane).


Siloxane Binding Energy Chart


About this element

Symbol: Si
Date of discovery: 1787
Name origin: Latin silex
Appearance: dark gray, bluish tinge
Discoverer: Antoine Lavoisier
Obtained from: silicon dioxide or silicate

Melting point: 1414 K
Boiling point: 2900 K
Density[kg/m3]: 2.33
Molar volume: 12.06 × 10-6 m3/mol
Protons/Electrons: 14
Neutrons: 14
Shell structure: 2,8,4
Electron configuration: [Ne]3s23p2
Oxidation state: 4
Crystal structure: cubic

Present in the sun and stars, silicon is the second most abundant element, making up over a quarter of the earth’s crust. Silicon is important in both animal and plant life. However, it can cause the serious lung disease silicosis if siliceous dust is inhaled. This dust, the most common form of silicon, is silvery gray with a bluish tinge. As an important ingredient in several materials such as glass, aluminum, and steel, silicon can be used to make bricks or concrete, computer chips, and silicone implants used in a variety of medical applications.


Nexsa G2 XPS

  • Micro-focus X-ray sources
  • Unique multi-technique options
  • Dual-mode ion source for monoatomic & cluster ion depth profiling

K-Alpha XPS

  • High resolution XPS
  • Fast, efficient, automated workflow
  • Ion source for depth profiling


  • High spectral resolution
  • Multi-technique surface analysis
  • Extensive sample preparation and expansion options
Style Sheet for Instrument Cards Original

Contact us

Style Sheet for Global Design System

Contact us

Style Sheet to change H3 to p with em-h3-header class
Style Sheet to change H2 style to p with em-h2-header class
Style Sheet for Products Table Specifications
Style Sheet for Global Design System
Style Sheet for Komodo Tabs
Style Sheet to change H3 to p with em-h3-header class
Style Sheet to change H2 style to p with em-h2-header class
Style Sheet for Products Table Specifications
Fix for left nav
Style Sheet for Support and Service footer
Style Sheet for Fonts
Style Sheet for Cards

Electron microscopy services for
the materials science

To ensure optimal system performance, we provide you access to a world-class network of field service experts, technical support, and certified spare parts.