TY - THES

T1 - Low temperature oxidation of sputtered thin films of molybdenum alloys

AU - List, Andrea Franziska

N1 - embargoed until null

PY - 2009

Y1 - 2009

N2 - Sputtered Mo thin films are widely used for thin-film-transistor liquid crystal displays (TFT-LCDs) due their relatively low electrical resistance and easy chemical patterning. Corrosion of Mo in the production process of TFT-LCDs causes serious problems and their storage in moist air leads to superficial oxidation. The lack of a systematic study of the effect of low contents of alloying elements in sputter deposited Mo films on their oxidation behaviour and corrosion resistance was the main driving force for the present investigation. The aim of this work was to synthesize Mo thin films alloyed with low contents of Ti, Cr, Ni, Nb, Ta or W, respectively, on glass substrates by magnetron sputter deposition from mosaic targets. Single phase Mo-based solid solutions were successfully prepared and the content of the alloying elements was in the range between 3.2 and 5.2 at.-%. Electrical resistivity values are comparable or only slightly higher than those of unalloyed Mo. Oxidation and corrosion properties have been determined in 85 % humidity at 85°C by use of exposure tests in a climatic test chamber and by potentiodynamic measurement and electrochemical impedance spectroscopy in 0.9 % NaCl aqueous solution at room temperature. To get more information about the nature of the oxide film, Raman spectroscopy and X-ray photoelectron spectroscopy investigations have been done. It was found that the alloying element Cr results in highest corrosion resistance due formation of a passive layer.

AB - Sputtered Mo thin films are widely used for thin-film-transistor liquid crystal displays (TFT-LCDs) due their relatively low electrical resistance and easy chemical patterning. Corrosion of Mo in the production process of TFT-LCDs causes serious problems and their storage in moist air leads to superficial oxidation. The lack of a systematic study of the effect of low contents of alloying elements in sputter deposited Mo films on their oxidation behaviour and corrosion resistance was the main driving force for the present investigation. The aim of this work was to synthesize Mo thin films alloyed with low contents of Ti, Cr, Ni, Nb, Ta or W, respectively, on glass substrates by magnetron sputter deposition from mosaic targets. Single phase Mo-based solid solutions were successfully prepared and the content of the alloying elements was in the range between 3.2 and 5.2 at.-%. Electrical resistivity values are comparable or only slightly higher than those of unalloyed Mo. Oxidation and corrosion properties have been determined in 85 % humidity at 85°C by use of exposure tests in a climatic test chamber and by potentiodynamic measurement and electrochemical impedance spectroscopy in 0.9 % NaCl aqueous solution at room temperature. To get more information about the nature of the oxide film, Raman spectroscopy and X-ray photoelectron spectroscopy investigations have been done. It was found that the alloying element Cr results in highest corrosion resistance due formation of a passive layer.

KW - Molybdän Dünnschichten sputtern Oxidation Korrosion

KW - Molybdenum films sputtering oxidation corrosion

M3 - Diploma Thesis

ER -