Definition: silicon oxide

Oxides contain at least one oxygen atom, and silicon oxide may refer to silicon dioxide (SiO₂) or silicon monoxide (SiO). Silicon dioxide is a hard, glassy mineral found in materials such as rock, quartz, sand and opal. In metal oxide semiconductor (MOS) chip fabrication, silicon dioxide is used to create the insulation layer between the metal gates of the top layer and the silicon elements below.

In contrast, silicon monoxide (SiO), the most common oxide of silicon, is used in optical coatings, lamps, mirrors and other optical applications. See silicon and silica gel.