The aim of the thesis is to examine the dielectric function Ta2O5 insulating layers in tantalum capacitors. The capacitor plugged in the regular mode represents a MIS structure of reverse direction. Three different factors can be determined for the residual current of the component according to its charge transmission mode: the ohmic, Pool–Frenkel, tunnel and Schottky. An apparatus was constructed by the author of the thesis to measure the temporary connection between residual current and rise of temperature of the tantalum capacitors. Annealing of three different sets of tantalum capacitors made by different producers was performed at the temperature of 400 K and nominal voltage of 35 V during the period of 20 days.The experiment has proved the residual current in the electric field changes with rising temperature in time as a result of the ion movement. The singular factors of the residual current are influenced during the process. By the “ion movement” is meant the ion drift influenced by the attached electric field and diffusion caused by the concentration gradient. First, the samples were being annealed for c. 2 x 106 s, and then the residual current was being regenerated under the voltage of 5 V for 106 s. The residual current values increased considerably after annealing, and decreased again to more or less the original level after the regeneration, some of the samples reaching even values bellow the original level. The VA characteristics of the samples measured before and after the process of controlled obsolescence, and after the regeneration prove not only a change in parameters of the different current factors, but also a change of the current transmission mechanism employed in the process.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:220243 |
| Date | January 2013 |
| Creators | Velísek, Martin |
| Contributors | Majzner, Jiří, Sedláková, Vlasta |
| Publisher | Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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