Solid-state is a common electronic term used to identify devices made from semi-conductor materials such as transistors or ICs. They produce far less heat and consume very little energy when compared to the old vacuum tubes. By far, silicon (Si) is the most widely used material in semiconductor devices. Its combination of low raw material cost, relatively simple processing, and a useful temperature range currently make it the best compromise among the various competing materials. Silicon used in semiconductor manufacturing is fabricated (grown) into large crystals called boules that are wide enough in diameter to allow the formation of 12 inch diameter wafers. Germanium (Ge) is another widely used material but its thermal sensitivity makes it less useful than silicon. Today, germanium is often alloyed with Silicon for use in very-high-speed SiGe devices. Gallium arsenide (GaAs) is also widely used in high-speed devices, but so far it has been difficult to form large-diameter wafers of this material, limiting the wafer diameter to sizes significantly smaller than silicon wafers thus making mass production of GaAs significantly more expensive than silicon. |