Characterization of sputtered amorphous platinum dioxide films

Amorphous platinum dioxide, a-PtO2, films are formed commonly during reactive sputtering of platinum at relatively high power density levels and high oxygen partial pressures. The structure of a-PtO2 is intermediate between the crystalline alpha and beta phases of this compound and either phase may form upon annealing or by lowering the power density during sputtering. Amorphous platinum dioxide is a semiconductor, and its resistivity depends on deposition parameters. Films of a-PtO2 are dense, chemically resistant, smooth, reflective, and have a hardness similar to titanium nitride. The films may be reduced in hydrogen at room temperature or in carbon monoxide at 200 °C to produce metallic platinum with crystallite sizes in the range of 5–10 nm. Any of these properties may be exploited to produce films that could be used in the development of sensors, optical materials, and in microelectronics.