Study On Electrosynthesis Of Pentakis (Diethy Lamido) Tantalum

Shrinkage of microelectronic device feature sizes implied that tantalumnitlide(TaN) films as the barrier materials, between copper and silicon, becomes the vital material in future generations of microelectronics devices(≤0.5μm). Of the many films forming precursors that are available, tantalum diethylamido(PDEAT) is realistically thought to be an optimal used precursors for metal organic chemical vapor deposition(MOCVD) of the barrier materials.The electrochemical behaviors of Ta in Bu4NBr diethylamine solutions were firstly investigated by measuring linear scan strpping voltammetry, and cyclic voltammetry. With the increase of the volume ratio(acetonitrile-diethylamine) and electrolyte concentration, the pitting potential Eb unchanged, Current density and the electrochemical dissolution of tantalum plate velocity increased. Morphology images and the shape of polarization curves confirmed the existence of pit corrosion on the electrode surface.The coarse PDEAT were then synthesized by electrochemical reactions of acetonitrile-diethylamine at sacrificial tantalum anode in the presence of Bu4NBr as a conductive additive. The effects of additive species, additive concentration, temperature, distance between anode and cathode, cell voltage on the electrochemical synthesis of PDEAT have been investigated. The optimum conditions were Bu4NBr 0.04mol/L, temperature 50℃, distance 0.4cm and cell voltage 50V.The purfied PDEAT were obtained by reduced pressure distillation from the coarse products. Fourier Transform Infrared spectra (FT-IR),1H nuclear magnetic resonance spectra (1H NMR) and XRD were applied to characterize as synthesized products. The results showed that the products are the PDEAT. The concentrations of impurity metallic elements in the sample were detected by ICP-MS, and the analysis results showed that the purity could come to 99.99%.Thermal properties of tantalum diethylamido was analysed by TG-DSC. The results of TG-DSC showed that the rate of mass loss was big enough to meet the demands of chemical vapor deposition. There was a temperature window between the temperature of volatilization and the temperature of thermal pyrolysis. Thermal analysis confirms that they were suited for metal organic chemical vapor deposition of TaN films.