High rate planar magnetron deposition of transparent, conducting, and heat reflecting films on glass and plastic

Films of indium tin oxide (ITO) and ZnO have been deposited by dc reactive planar magnetron sputtering of metal targets in an Ar/O₂ atmosphere. Control of film stoichiometry was achieved through an applied rf bias to the substrate, a reactive gas baffle surrounding the target, and computer control of all parameters in the sputtering process, such as cathode voltage, gas flow, and substrate bias. Films were deposited on cold glass substrates as well as on rolls of polyester sheet. Both the ITO and ZnO films were highly conducting, visually transparent, and infrared reflecting. The success of this deposition technique applied to ZnO films identifies ZnO as a new candidate for transparent, heat reflecting coatings.