ESCA study of sputtered platinum films

Characterization of oxidized platinum surfaces by X-ray photoelectron spectroscopy

Thin‐film oxides of platinum have been prepared by reactive sputtering and characterized primarily by x‐ray diffraction (XRD) and Raman scattering. Different phases of the Pt‐O system were obtained by adjusting sputtering parameters such as gas composition, deposition rate, and substrate temperature. Optimum conditions for producing crystalline α‐PtO2 and PtO were identified. Raman spectra of α‐PtO2 films show two sharp lines at 514 and 560 cm−1, in agreement with those from commercially available powders. XRD and high‐resolution scanning electron microscopy (HRSEM) analyses indicate that these samples have a poorly crystallized structure with lack of order along the c axis. The Raman spectra from PtO show two broad peaks at 438 and 657 cm−1, close to the lines seen in PdO, which has the same structure as PtO. Estimates from XRD line broadening and HRSEM photographs indicate mean crystallite sizes on the order of 300 A. Infrared reflectivity spectra yield two of the three ir‐active phonons, and along with...

Growth and characterization of reactively sputtered thin‐film platinum oxides

Glow discharge sputtering

Study of multilayer surface oxidation of platinum by electrical resistance technique

An oxide phase which is isostructural with PdO has been obtained as a thin film by reactive dc diode sputtering of Pt in argon‐oxygen mixtures. Films in which this is the only crystalline phase observed have been prepared; they have a density of 13.5±1.0 g/cm3. The oxide phase is unstable at temperatures above 500 °C, and the film is converted to platinum. Thermogravimetric analysis of the films indicates that the original composition is close to PtO. Mixtures of PtO and Pt can also be obtained and the temperature coefficient of resistance of the films becomes more negative with increasing PtO content; values between +1800 and −25 000 ppm/°C have been measured.

C. D. Bennewitz

Papers

Formation of PtO films by reactive sputtering