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Customer complaints from quality point of view
Voborník, Petr ; Hégr, Ondřej (referee) ; Novotný, Radovan (advisor)
This work deals with issues of customer complaints management from quality point of view. The general aim is to introduce complaints management process and complaints evaluation. It introduces key monitored parameters of complaint management process. There is introduced complexity of complaints management process. Design of database system IS. Reporting of complaints.
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The Use of AFM Measurement Method in Crystalline Silicon Solar Cells Technology
Mojrová, Barbora ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
This thesis deals with the use of Atomic Force Microscopy (AFM) and Kelvin Probe Force Microscopy (KPFM) in solar cells production. Both techniques measure surface properties using interactions between surface and tip that progressively scans entire surface of the sample. Atomic force microscopy allows three dimensional imaging of surface structure. Kelvin probe force microscopy is used to measure the contact potential difference on the sample surface. There are described experimental measurements of monocrystalline and multicrystalline substrates after various etching processes using AFM. By using KPFM the contact potential difference was measured on dielectric layers PSG, SiOX, SiNX and Al2O3 and on selective emitter structures. All experiments described in this work were carried out at the Solartec Ltd. workplace and they completely correspond with the actual technology of crystalline solar cells production.
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Lifetime measurement of current carriers in silicon solar cells structures
Macháček, Martin ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This thesis deals with a lifetime measurement of current carriers in silicon solar cell structures. In the first chapter there is a description of several recombination models and their participation at a final effective lifetime value. By using these recombination models in a computer simulation it is possible to receive approximate evaluation of some important silicon solar cell structure parameters. The PC1D simulation program was used for this thesis. For the lifetime measurement of real test-wafers two methods were used: QSSPC (quasi-steady-state photoconductance) and MW-PCD (microwave photoconductance decay). There is a detail description of these methods, used measurements machines and differences between both of them in the chapter four. The main objective of the thesis is mentioned in the last chapter, which is mainly focused on a chemical passivation of silicon wafers and deals with a problem of post-passivation wafer cleaning. There are three passivation techniques mentioned: the iodine in ethanol solution, the iodine and polymer in ethanol solution and the quinhydron in methanol solution. In two cases a results, that are adequate to return the tested wafers in the manufacture process, were achieved.
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Modification of silicon solar cells structure
Strachala, Dávid ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
The aim of the work is to create a coherent overview of the silicon monocrystaline solar cell in terms of the physical principle of the structure and sequence of technological operations necessary for its production. The effect of individual manufacturing steps is discussed in relation to the requirement of decreasing recombination, optical and ohmic losses of the monocrystalline solar cell. Due to a theoretical assumption, one-dimensional model of solar cell was created in a PC1D software that was later optimized to achieve the highest possible efficiency. Using the available technologies, final model of the solar cell is manufactured in Solartec company and in the end of the work compared with the output of simulation.
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Value stream analysis and improvement
Malec, Tomáš ; Hégr, Ondřej (referee) ; Novotný, Radovan (advisor)
This thesis deals with the general analysis and value stream improvement. The theoretical part describes the difference between functional and procedural model of company management, mutual benefits and disadvantages of these systems. The thesis deals with the mapping process, subdivision maps and methodology of process maps creation. The work also includes software analysis for process mapping. Next section contains search of selected optimization tools and methods to improve production flow and description of the principles of controlled documentation. In the practical part is realized mapping process of bachelor studies at FEKT and map of production process at ABB switchgear.
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High-Voltage Devices in Smart Power Technology
Šeliga, Ladislav ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
Tato práce se zabývá popisem základních vlastností LDMOS tranzistorů. V první části práce jsou rozebrány vlastnosti LDMOS tranzistorů, jejich základní parametry a techniky pro vylepšení parametrů těchto tranzistorů. V další části je rozebrána spolehlivost LDMOS tranzistorů, tato část popisuje bezpečnou pracovní oblast (SOA), injekci horkých nosičů (HCI) a negativní teplotní stabilitu (NBTI). Poslední teoretická část popisuje používané modely pro simulaci ESD událostí. Praktická část práce je zaměřena na simulaci základních parametrů PLDMOS a NLDMOS tranzistorů, porovnání simulovaných a změřených koncentračních profilů. Dále se práce zabývá simulacemi změny geometrických parametrů PLDMOS tranzistoru a vliv těchto změn na elektrické parametry. Poslední část práce tvoří TLP simulace, které zkoumají elektrické vlastnosti PLDMOS tranzistoru při použití jako ESD ochrana.
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Study of organic based structures for solar cells
Kostovčík, Tomas ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
Práce se zabývá problematikou využití organických materiálů v solárních článcích. V úvodu práce jsou rozebrány a vysvětleny jednotlivé fyzikální a chemické jevy, které ovlivňují vlastnosti organických materiálů. Práce pokračuje rozborem působení rozličných struktur organických solárních článků na jejich vlastnosti. Dále je popsána technologie výroby vzorku a jsou v ní uvedeny výsledky měření fotovodivosti.
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Fixed-charge examination by surface energy measurement
Mojrová, Barbora ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
This work is deal with development of alternative method measuring fixed charge in thin dielectric layers by surface tension. Presence fixed charge takes effect so-called Back Surface Field (BFS), which helps to decrease surface recombination velocity on back side of solar cell. In work is described experimental measuring on dielectric layers Al2O3, AlN, SiNx, Y2O3 and PSG deposit on crystalline silicon wafers. Surface tension (it is the same like surface free energy) is analyzed from contact angle size using See System.
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