Abstract: A method of sputtering a platinum exhaust gas electrode onto a vitrified zirconia thimble for an electrochemical-type exhaust gas oxygen sensor. Porous high surface area films are consistently deposited at high rates. A DC magnetron cathode assembly having a magnetic field strength of at least 500 gauss across its target face is used at a sputtering power of about 4-9 kilowatts. A thimble-target spacing of less than about 3.0 cm, a pressure less than about 10 millitorr, a sputtering atmosphere consisting essentially of more than about 50 percent nitrogen and/or oxygen, an electrically isolated deposition surface, and an electrically floating reference electrode precoated on the zirconia thimble surface are used.

Abstract: A planar magnetron sputtering cathode assembly especially for simultaneously heating and coating substrates is also adaptable to a cool substrate operation. The cathode assembly features an efficient magnetic circuit using magnet assemblies enclosed within the sputtering chamber using minimal air gaps for magnetic efficiency and high-strength magnets to produce a high field at the sputtering target, and stainless steel cladding of the magnets to protect the magnets as well as to prevent out-gasing from the magnet material. A heat sink fills the space between the magnets to provide excellent cooling of the magnets as well as cooling of the target which seats directly on the heat sink. The target is held in place by bolts to facilitate rapid target changing.

Abstract: A method of sputtering a platinum exhaust gas electrode onto a vitrified zirconia thimble for an electrochemical-type exhaust gas oxygen sensor. High yields of sensors having fast response times as formed are consistently produced. The exhaust gas outer electrode is sputtered onto the thimble after first forming an inner electrode, using a rate that significantly heats the thimble. The first electrode is maintained electrically isolated from the exhaust electrode during sputtering, and is maintained at a different electrical potential.