http://en.wikipedia.org/wiki/Silicon
Silicon (IPA: /ˈsɪlikən/, Latin: silicium) is the chemical element that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. As the eighth most common element in the universe by mass, silicon occasionally occurs as the pure free element in nature, but is more widely distributed in dusts, planetoids and planets as various forms of silicon dioxide or silicate. On Earth, silicon is the second most abundant element (after oxygen) in the crust, making up 25.7% of the crust by mass.

is its use as the fundamental substrate in manufacturing electronics integrated circuits such as computer chips, and discrete active devices such as power transistors.