Leakage current and Physical properties of Tantalum oxide thin films for Micro capacitor integration

Tantalum oxide (Ta₂O₅) were grown on the Ti and Ti-O₂ layers as a oxide barrier using RF-sputtering method. Measurement of physical and dielectric properties of the reactive sputtered Ta₂O₅ as two forms of simple MOS structure, states that the amorphous Ta₂O₅ grown on Ti gave high dielectric constant (ε_r=30~70) and high leakage current (10^-1~10^-4 A/cm²), whereas relatively low dielectric constant (~10) and low leakage current (~10^-10 A/cm²) were observed in the amorphous Ta₂O₅ deposited on the Ti-O₂. As a result, the Ta₂O₅/Ti capacitor exhibits three dominant conduction mechanism regimes contributed by the ohmic emission at low electrical field, by the Schottky emission at intermediate field and by the Poole-Frenkel emission at high field. In the case of Ta₂O₅/TiO₂ capacitor, the two conduction mechanisms, the Ohmic and Schottky emissions, governs the leakage current density behavior.