<p>Bismuth titanate Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>, is one of the bismuth based layered ferroelectric materials that is a candidate for replacing the lead based ferroelectric materials in for instance non-volatile ferroelectric random access memories (FRAM). This is due to the fact that the bismuth based ferroelectrics consists of pseudo perovskite units sandwiched in between bismuth oxide layers, which gives them a better fatigue nature.</p><p>In this thesis thin films of Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12 </sub>have been deposited by chemical vapour deposition (CVD) using the metal iodides, BiI<sub>3</sub> and TiI<sub>4</sub> as precursors. Films grown on MgO(001) substrates were found to grow epitaxially. The electrical properties were determined for films grown on Pt-coated silicon and good properties such as a high dielectric constant (ε) of 200, low <i>tan</i> δ of 0.018, a remnant polarisation (<i>P</i><sub>r</sub>) of 5.3 μC/cm<sup>2</sup> and coercive field (E<sub>c</sub>) as high as 150 kV/cm were obtained. Thin films in the Bi-Ti-O system were also deposited by atomic layer deposition (ALD) using metalorganic precursors.</p><p>In addition to the ternary bismuth titanates, films in the binary oxide systems <i>i.e.</i> bismuth oxides and titanium oxides were deposited. Epitaxial TiO<sub>2</sub> films were deposited both by CVD and ALD using TiI<sub>4</sub> as precursor. The rutile films deposited by ALD were found to grow epitaxially down to a temperature of at least 375 ¢ªC on α-A1<sub>2</sub>O<sub>3</sub>(0 1 2) substrates. The TiO<sub>2</sub> ALD process was also studied <i>in-situ</i> by QCM. Different bismuth oxides were deposited by halide-CVD using BiI<sub>3</sub> as precursor on MgO(0 0 1) and SrTiO<sub>3</sub>(0 0 1) substrates and the results were summarised in an experimental CVD stability diagram. The Bi<sub>2</sub>O<sub>2.33</sub> phase was found to grow epitaxially on both substrates.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-552 |
| Date | January 2000 |
| Creators | Schuisky, Mikael |
| Publisher | Uppsala University, Department of Chemistry, Uppsala : Acta Universitatis Upsaliensis |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, text |
| Relation | Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 594 |
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