Silicon wafers are available in a variety of diameters from 25.4 mm (1 inch) to 300 mm (11.8 inches). Semiconductor fabrication plants (also known as fabs) are defined by the diameter of wafers that they are tooled to produce.
1-inch (25 mm). 2-inch (51 mm). 3-inch (76 mm). 4-inch (100 mm). 5-inch (130 mm) or 125 mm (4.9 inch). 150 mm (5.9 inch, usually referred to as 6 inch). 200 mm (7.9 inch, usually referred to as 8 inch). 300 mm (11.8 inch, usually referred to as 12 inch). 450 mm (17.7 inch).