There are many different types of wafer fabrication equipment, but most are focused on growing, depositing, or removing materials from wafers. Oxidation systems, epitaxial reactors, diffusion systems, ion implantation equipment, physical vapor deposition systems, chemical vapor deposition systems, photolithography equipment, and etching equipment are a few examples of wafer fabrication equipment. Until the circuit is fully constructed on the wafer, these devices alternately deposit and remove various materials in predetermined patterns from the wafer.