PhD Thesis Arne Lüker final version V4 - Cranfield University

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PST directly on SiO2
of PST onto SiO2 or directly onto Si, where the native oxide was removed prior to the
deposition via an HF-dip, Fig. 7.11. Furthermore, due to the well known Pb diffusion into
Si or/and SiO2, the above described formation of the interface between SrTiO3 and
Si/SiO2 holds in first approximation for PST as well. After the interface is established, the
growth of further layer of PST follows the normal observed pattern.
7.2 Auger Analysis of PST on SiO2
Auger spectroscopy allows the study of the compositional change in thin films and the
interface to the substrate. One single film of PST was deposited and annealed at 650°C
on a silicon substrate with 200 nm thermal oxide. Between each measurement the sample
was etched for 100 sec using the ion-sputtering unit with an ion current of 2kV and
0.75µA (1.5 mW). Fig 7.11 shows the compositional change in the PST and interfacial
layer.
Fig. 7.11: Auger spectra of one layer PST and its interface to the Si/SiO2 substrate