Monocrystalline Silicon

Monocrystalline silicon or single-crystal Si, or mono-Si is the base material of the electronic industry. It consists of silicon in which the crystal lattice of the entire solid is continuous, unbroken (with no grain boundaries) to its edges. It can be prepared intrinsic, i.e. made of exceedingly pure silicon alone, or doped, containing very small quantities of other elements added to change in a controlled manner its semiconducting properties. Most silicon monocrystals are grown by the Czochralski process, in the shape of cylinders up to 2 m long and 45 cm in diameter (figure on the right), which, cut in thin slices, give the wafers onto which the microcircuits will be fabricated.

Single-crystal silicon is perhaps the most important technological material of the last decades (the "silicon era"), because its availability at an affordable cost has been essential for the development of the electronic devices on which the present day electronic and informatic revolution is based.

Monocrystalline is opposed to amorphous silicon, in which the atomic order is limited to short range order only. In between the two extremes there is polycrystalline silicon, which is made up of small crystals, known as crystallites.