Effect of Oxygen Partial Pressure on the Structural and Electrical Properties of DC Sputtered (Ta2O5)0.85(TiO2)0.15 Thin Films on Si

Thin films of (Ta2O5)(0.85)(TiO2)(0.15)) were deposited on p-Si (100) by DC reactive magnetron sputtering at various oxygen partial pressures in the range 3x10(-2) - 9x10(-2) Pa and annealed in air for 1 hour at 700 degrees C. The structural properties of the (Ta2O5)(0.85)(TiO2)(0.15) films were studied and the electrical properties of Al/(Ta2O5)(0.85)(TiO2)(0.15) gate stacks formed on p-Si substrates were systematically investigated. The leakage current density of the films deposited at 3x10(-2) Pa was 6.97x10(-6) A/cm(2) (at a gate bias voltage of 1.5 V) and it was decreased to 1.75x10(-8) A/cm(2) with the increase of oxygen partial pressure to 9x10(-2) Pa. The current conduction mechanism of the (Ta2O5)(0.85)(TiO2)(0.15) films was analyzed and compared with mechanisms of Poole-Frenkel and Schottky emissions.