Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 31: Organic semiconductors
HL 31.8: Talk
Wednesday, March 29, 2006, 16:15–16:30, POT 51
Anodized gate dielectrics: Preparation, characterization and organic-based transistor application — •J. Pflaum1, S. Goettling2, J. Brill2, N. Fruehauf2, and E. Margallo-Balbás3 — 13rd Inst. of Physics, Stuttgart University, 70550 Stuttgart — 2Chair of Display Technol., Stuttgart University, 70550 Stuttgart — 3Electr. Instr. Lab., TU-Delft, 2628 CD Delft, The Netherlands
The application of organic-based thin film transistor (TFTs) requires the controlled preparation of thin high-k gate dielectrics in combination with low-cost, large-area processes. As a possible approach, we investigated the growth and morphology of the anodized gate dielectrics Al2O3 and Ta2O5. The anodization was carried out for glass and plastic substrates using various electrolytes. For the analysis of thickness, interface roughness and chemical composition, small-angle X-ray diffraction was exploited and modelled by the Parratt-formalism. The resulting data indicate the formation of oxide layers with defined stoichiometry and sharp interfaces. An influence of the respective electrolyte on the structural properties and on the breakthrough field strength could be clearly deduced. The obtained breakthrough fields up to 5MV/cm indicate the suitability of anodized gate-dielectrics in organic-electronic devices. First application of anodized dielectrics in pentacene TFTs on glass and plastic substrates will be demonstrated. As a key result, pentacene TFTs on Al2O3 on glass and on plastic substrates provide reliable transistor characteristics with hole mobilities of 0.1cm2/Vs and on/off-ratios of 107-108. Financial support by DFG (Project Pf 385/2), EU (FlexiDis) and Landesstiftung Baden-Württemberg is acknowledged.