Silicon Wafer is a thin slice of semiconductor material, typically silicon crystal, used in the fabrication of integrated circuits and other microdevices. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication processes, such as doping, ion implantation, etching, thin-film deposition of various materials, and photolithographic patterning. The quality of the wafer is critical as it determines the integrity and performance of the finished electronic or photonic device.
Wafers are predominantly made from single-crystal silicon, produced using the Czochralski process, which allows for the precise control of impurity levels. The diameter of wafers has progressively increased over the years—from 25 mm to 300 mm and beyond—to accommodate more circuits and enhance overall production efficiency. Surface flatness and cleanliness are maintained meticulously to avoid defects that could propagate during device manufacturing. Advanced wafers may also involve epitaxial growth, where additional silicon layers are deposited on the substrate to create a heterostructure, crucial for devices like high-frequency transistors.
