Strained silicon

Strained silicon is a layer of silicon in which the silicon atoms are stretched beyond their normal interatomic distance. This can be accomplished by putting the layer of silicon over a substrate of silicon germanium. As the atoms in the silicon layer align with the atoms in the silicon germanium layer where the atoms are farther apart, the links between the silicon atoms become stretched - thereby leading to strained silicon. Moving these silicon atoms farther apart reduces the atomic forces that interfere with the movement of electrons through the transistors, resulting in better chip performance and lower energy consumption. These electrons can move 70% faster allowing strained silicon transistors to switch 35% faster. More recent advances include deposition of strained silicon using metalorganic vapor phase epitaxy (MOVPE) with metalorganics as starting sources, e.g. silicon sources (silane and dichlorosilane) and germanium sources (germane, germanium tetrachloride, and isobutylgermane).