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U. Schmid, M. Grosser:
"Electrical performance of Ti/Pt thin films on glass-ceramic substrates after high temperature loading";
Applied Physics A: Materials Science & Processing, 96 (2009), S. 921 - 932.

In this study, the influence of post-deposition annealings
(PDA) up to temperatures of TPDA = 700°C on the room-temperature resistivity of e-beam evaporated titanium/platinum (Ti/Pt) bi-layers on low temperature cofired (LTCC) substrates covered with a glass encapsulate is investigated. The thickness of the platinum top layer
is varied between 24 and 95 nm (titanium film thickness: 5 nm) and between 23 and 90 nm (titanium film thickness: 15 nm), respectively. In the "as-deposited" state and up to post-deposition annealing temperatures of TPDA = 450°C, the film resistivity is linearly correlated with the reciprocal value of the platinum film thickness according to the size effect. When applying, however, solely the Fuchs-Sondheimer model for evaluation, the effective mean free path for electrons is substantially above the value reported for crystalline platinum at room temperature. Compared to similar investigations on smooth Si/SiO2 substrates yielding interpretable
results within this theoretical approach, this is due to the increase
of the thickness-dependent fraction in film resistivity which is strongly affected by the enhanced LTCC/glass surface roughness. At TPDA > 600°C, diffusion of titanium into the platinum top layer and the roughening of the LTCC/glass substrate dominate the electrical behavior, both causing an increase in film resistivity above average. In contrast to Si/SiO2 substrates, thermal induced grooving effects in the Pt top layer play a minor role as the temperature coefficients
of expansion of metallization and glass-ceramic substrate match better and the effective temperature difference for stress generation is lower due a glass softening temperature of about 450°C.

http://dx.doi.org/10.1007/s00339-009-5255-6