Ultrathin metal oxidation for vacuum monitoring device applications

The oxide growth on thin metal films at room temperature has been investigated in terms of resistance change during oxidation. These data have been interpreted using the extended Cabrera–Mott theory of oxidation by Boggio. The resulting oxide thickness as well as the oxidation kinetics was found to depend on pressure. According to this dependence, oxidation of ultrathin metal films can be applied for monitoring the vacuum quality inside an evacuated environment. The performance of aluminum and copper sensing layers are compared with respect to sensor lifetime and response. Furthermore, the theoretically evaluated and resistively measured oxide thicknesses are verified by TEM studies.