A wafer is a thin slice of semiconductor material, such as a silicon crystal, used in the fabrication of integrated circuit microchips, and other microdevices. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication process steps such as doping or ion implantation, etching, deposition of various materials, and photolithographic patterning. Several types of solar cells are made from such wafers. A solar wafer is a circular solar cell made from the entire wafer rather than cutting into smaller rectangular solar cells.