Definition: SOI

(Silicon On Insulator) A chip architecture that increases transistor switching speed by reducing capacitance (build-up of electrical charges in the transistor's elements), and thus reducing the discharge time. The power requirement is also reduced in some designs. The SOI technique creates the transistors on a thin top silicon layer that is separated from the silicon substrate by a thin insulating layer of glass or silicon dioxide. One method of forming this insulating layer is the Separation by Implantation of Oxygen (SIMOX) technique, which implants oxygen into the wafer under intense heat.