Solar-Grade Silicon

What is Solar-Grade Silicon?

Solar-grade silicon is a form of high-purity silicon (99.9999% pure) that is produced exclusively for the solar industry and does not typically include general semiconductor-grade silicon.

Key Takeaways:

  • Solar-grade silicon is a form of highly purified silicon for use in solar manufacturing.
  • The Siemens process is the refining process used to create solar-grade silicon.
  • Solar-grade silicon is used to create n-type silicon and p-type silicon for use in solar panels.

Understanding Solar-Grade Silicon

Solar-grade silicon is a form of highly purified silicon that is produced for the solar industry and is typically produced through the Siemens process. It is 99.9999% pure and has several identifying characteristics that make it desirable as solar cell material.

Solar-grade silicon is produced from lesser grade silicon by a chemical purification process, called the Siemens process, which involves the distillation of various silicon compounds at very high temperatures. 

To the naked eye, solar-grade silicon appears to have large crystals that give polycrystalline silicon a very distinctive appearance. Polycrystalline solar-grade silicon is the most common form of solar-grade silicon used in photovoltaic panels due to its significantly lower cost than monocrystalline silicon.

In addition, there are two main ‘flavors’ of solar-grade silicon that are used to make solar panels: n-type and p-type silicon. In each of these types of solar-grade silicon, an electrical charge is created within the material (negative and positive, respectively) that, when combined, facilitate the electric charge that is created when photovoltaic panels are exposed to sunlight.

Related Terms

N-Type Silicon – N-type silicon is silicon that has been chemically bonded with phosphorus gas to create an electrically conductive, negatively charged, form of silicon.

Polycrystalline Silicon – Polycrystalline silicon is a form of high-grade silicon for use in the solar industry and refined by a chemical purification process called the Siemens process.

Photovoltaic Panel – A panel of semiconducting material that converts sunlight into electrical energy through the photovoltaic effect.