Published online by Cambridge University Press: 11 March 2016
Two different methods were used to synthesize 200 nm thick single-phase, orthorhombic-PtSi films: (i) e-beam co-evaporation (EBC) of Pt and Si onto r-sapphire substrates and (ii) solid-state reaction (SSR) of sputtered Pt films on Si (100) wafers. Morphology, electrical conductivity, and crystalline structure were characterized for as-grown films and for films annealed in air at 1000 °C via scanning electron microscopy (SEM), 4-pt conductivity measurements, and in situ X-ray diffraction (XRD). As-grown EBC films exhibit columnar grain morphology and slight (101) crystalline texture, while SSR films exhibit granular morphology with many voids and a strong (002) texture. Above 600 °C, EBC PtSi films rapidly oxidize to form crystalline Pt3Si and amorphous SiO2 phases. Around 1000 °C, the Pt3Si phase melts and c-Pt grains nucleate. After air annealing for 6 h at 1000 °C, room-temperature XRD shows that the oxidized EBC films consist of Pt3Si and Pt phases within a SiO2 matrix and become electrically insulating. SSR films initially form with a (002) o-PtSi orientation and above 900 °C they recrystallize to preferred (101) texture and exhibit an unchanged electrical conductivity and a stable film morphology during 48 h of air annealing at 1000 °C. Separate oxidation mechanisms are proposed for the two film types.