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Development of alternative processes for top electrode deposition on OLED based on physical vapour deposition process - Entwicklung alternativer Verfahren zur Abscheidung von OLED-Deckelektroden basierend auf PVD-Prozessen
Art der Abschlussarbeit
Dissertation
Autoren
- Gil, Tae Hyun
Betreuer
- Prof. Dr.-Ing. Hubert Lakner
Weitere Betreuer
Herr Prof. Dr. Karl Leo
Abstract
The large area fabrication of organic light emitting diode (OLED) requires a reliable and stable process for electrode deposition in order to extend the equipment uptime. Magnetron sputtering is candidated as a suitable metal deposition method, but serious damages in the OLED are generally observed. The degradation mechanisms based on the working principle of the magnetron sputtering are investigated using various measurements with variation of the process parameters. It is proved that the high leakage current is the result of metal penetration into the organic layers during the sputter process. With a special facing target sputtering (FTS) system, the aluminium deposition could be successfully demonstrated after the optimization of the process parameter with very low damage. However, due to very low deposition rate, the application of this process is difficult for a mass production. A bipolar pulsed double magnetron sputtering (DMS) also enables the metal deposition on the organic thin film device without damage, and, furthermore, the DMS system allows a very short process time which is required for mass production. It is therefore expected that this method can be successfully applied to the fabrication of OLED lighting and displays. rn Attemps to deposit transparent conducting oxide (TCO) material on organic layers are also performed using FTS system. Indium tin oxide (ITO), which is widely used as a transparent electrode, is deposited by various process parameters in order to investigate electrical and optical properties of the thin film. With the results, ITO films are deposited on organic layers, but the OLEDs show high damage level and short lifetime. Based on the results, possible methods that can achieve low damage deposition of TCO material are suggested.
Url/Urn/Doi
ISBN 978-3-942710-54-1
Schlagwörter
OLED Technische Optik Optoelektronik
Berichtsjahr
2011