10.1.1 Wafers and Crystal Preparation

The wafers of crystalline silicon are the basis on which integrated circuits are built. This substrate serves both as the medium on which the integrated circuits are built and as part of the electrical circuit itself. First large cylinders of crystalline silicon are grown to lengths of up to two meters and then the wafers are sliced from these cylinders, which are lightly doped with either n- or p-type dopants.

Currently used wafers have diameters of up to twelve inches (300mm). The crystals are usually cut so that their surface is oriented in the <100> direction. The slices are generally about $500\mu m$ thick. Much thinner slices are acceptable concerning the electrical properties of the wafers, but thicker slices are used since they are easier to handle and less likely to warp.