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M. Grosser, U. Schmid:
"The impact of annealing temperature and time on the electrical performance of Ti/Pt thin films";
Applied Surface Science, 256 (2010), 14; 4564 - 4569.

In this study, we focus on the influence of annealing time tPDA (i.e. 30 min and 630 min) on the roomtemperature
resistivity of electron-beam-evaporated titanium/platinum thin films when exposed to
thermal loads up to temperatures TPDA of 700 ◦C. The titanium has a fixed thickness of 5 nm and serves
as an adhesion layer. The thickness df,Pt of the platinum top layer is varied between 21 and 97 nm. Up to
annealing temperatures of 450 ◦C, the film resistivity of the bi-layer system is linearly correlated with the
reciprocal platinum film thickness independent of tPDA, as expected from the size effect. At tPDA = 30 min,
the change in intrinsic film stress dominates the electrical behavior in this annealing regime, predominantly
at large df,Pt values. Compared to tPDA = 630 min, however, the increase in resistivity especially at
low platinum film thickness is substantially larger demonstrating that titanium starts to diffuse at these
long annealing times even at moderate temperatures. At TPDA = 600 ◦C, the diffusion of titanium into the
top layer leads to an enhanced increase in film resistivity f, especially at low platinum thicknesses and
low annealing times, as the mean penetration depth of diffused titanium is under these conditions in
order of df,Pt. Above TPDA = 600 ◦C, f is slightly increased at tPDA = 30 min. At tPDA = 630 min, however, the
film resistivity is decreased at df,Pt < 58 nm. This is attributed to grain growth and re-crystallization effects.
Furthermore, the mean penetration depths of titanium substantially exceed df,Pt resulting predominantly
in TixOy formation on the top film surface and hence, having low impact on Pf.

Platinum Thin film Resistivity High-temperature annealing Diffusion

http://dx.doi.org/10.1016/j.apsusc.2010.02.048