Determination of diffusion in polycrystalline platinum thin films

Abstract

Grain boundary diffusion of titanium through platinum thin films has been carried out in the temperature range from 200 to 600°C. Five different platinum/titanium bilayer thicknesses, from 35 to 800 Å Pt, were annealed in 5% O 2 /95% N 2 . The accumulation of titanium at the platinum surface layer was measured by x-ray photoelectron spectroscopy ͑XPS͒ to determine the grain boundary diffusion coefficient (D b ). Diffusivity values were calculated based on two different analysis methods assuming type C kinetics. For Pt layers thicker than 200 Å, the activation energy (Q b ) for titanium diffusion was found to be 118Ϯ15 kJ/mol ͑1.22Ϯ0.16 eV͒. For Pt layers thinner than 200 Å, there was a thickness dependence on the diffusion kinetics, resulting in activation energies as low as 20Ϯ4 kJ/mol ͑0.21Ϯ0.04 eV͒. XPS results gave no evidence for any Pt-Ti alloy formation in these layers. The suppression of alloy formation may be attributed to the presence of oxygen at the Pt/Ti interface during layer deposition. The quantitative analysis of titanium interdiffusion in platinum provides valuable information regarding Pt/Ti surface concentrations in thin-film chemical sensors, and for understanding changes in operational characteristics of platinum electrodes.

Contributions to the dielectric losses of textured SrTiO3 thin films with Pt electrodes

“…3) showed that the density of threading dislocations (labeled "O" and "A" in Fig. 3) was in the order of 5¥10 SIMS showed that the Pt electrodes on the Ti adhesion layers contained Ti, consistent with findings by others [18][19][20]. The influence of Ti underneath (111) textured Pt electrodes on perovskite film texture is well documented [21,22].…”

Characteristics and mechanism of tunable work function gate electrodes using a bilayer metal structure on SiO/sub 2/ and HfO/sub 2/

“…The other systems studied would be expected to exhibit appreciably higher interdiffusion based on their lower solidus temperatures [14]. For example, DiBattista and Schwank [15] examine diffusion of Ti in Pt thin films and report a range of diffusivities which are reasonably consistent with the diffusivity of cm we extract from the diffusion lengths associated with the gradual transition observed in the work function measurements. Measurements in the Nb/W system show a diffusivity of around times smaller [13].…”

Coalescence and sintering of Pt nanoparticles:in situobservation by aberration-corrected HAADF STEM

“…Note that L/L = 0 when surface diffusion is dominant since this is a non-densifying diffusion mechanism. Based on extrapolations to room temperature from previously measured values of the diffusivities at higher temperatures, we expect surface diffusion to dominate for Pt at or near room temperature since the surface diffusivity is at least many orders of magnitude faster than other diffusivities and the surface areas are also much higher for nanoparticles compared to bulk materials [12][13][14][15].…”