Tantalum oxide breakdown voltage

This chapter discusses the preparation of tantalum oxide thin films using the sol-gel method, which we believe is promising as a practical method for producing dielectric thin films whose dielectric constants and breakdown voltages are both comparatively high. Tantalum oxide films are good candidates for insulators in LSI devices, EL devices, and film capacitors [4]. Reports on the for-... 

To obtain a tantalum oxide thin film with a high dielectric constant and favorable breakdown voltage characteristics, it is best to fire the film at 400°C. 

By virtue of the high breakdown potential of the oxide film (approximately 155 V in sea water and 280 V in low conductivity water of pH = 7) tantalum has found use as a substrate for platinum in impressed-current cathodic-protection anodes, which can be used at high impressed voltages (50 V) and high current densities. However, because of its lower cost, niobium is preferred for systems that have to operate at high voltages... 

On aluminum and other valve metals (titanium, zirconium, hafnium, tantalum, and niobium), thicker anodic oxide films can be grown because the oxides are insulators. Thick films of 100 pm are generally porous, whereas the barrier films are thinner (<1 pm). As indicated earlier, the anodic oxide films formed on valve metals exhibit dielectric breakdown at high voltages. 

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