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

Abstract

Tantalum oxide (Ta2O5) were grown on the Ti and Ti-O2 layers as an 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 (epsivr=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