Include Product Page SiO2_Material Information

α-quartz, SiO2 

  • Name: Single Crystal Silicon dioxide (SiO2), α-quartz
  • Lattice parameter:a=4.914 Å, c=5.405 Å 
  • Crystal Structure: Trigonal
  • Commonly used as substrate for: SiO2, GeO2, TiO2, ZnO2, GaPO4
  • Surface Roughness: Ra <0.5 nm (measured 5x5 µm AFM scan)
  • Available Dimensions: 5x5 mm to 2 inch diameter and customized
  • Comes as X-cut (11-20), Y-cut (10-10) (90 degrees to X-cut), Z-cut Z-cut  (0001)
  • Single or double side polished
  • Next day delivery                     

 SiO2 has a trigonal structure (considered part of hexagonal structure therefore used 4 indices notation.

SiO2 has a trigonal structure (considered part of hexagonal structure therefore used 4 indices notation.

There are several polymorphs of silicon dioxide (SiO2) and there are a few types of silicon dioxide important for thin film applications. This can be in thin films or substrates, amorphous or crystalline. Here, we are referring to the crystalline form of SiO2 also known as  α-quartz, not to be confused with fused quartz which is the amorphous form of SiO2.

At normal pressure trigonal quartz (α-quartz) will transform into hexagonal β-quartz at 573°C and later to cubic β-cristobalite at 1050°C. At 1705°C β-cristobalite finally melts. So if using quartz as a substrate it is advisable to stay under the β-quartz transition at 573°C.

Quartz single-crystal substrates are transparent and have excellent thermo-mechanical properties, low coefficient of thermal expansion, excellent mechanical and piezoelectric properties. Single-crystal quartz substrates are used in electronics, precision optics, laser technology, optical communications, X-ray optics and pressure sensors.

As a well studied and well-known material, SiO2 is often used to grow thin films for optical experiments however it does also support epitaxial growth of some films.Quartz single crystals are also sometimes used as targets for pulsed laser deposition to grow a dielectric layer.