Effects of Electrode Materials and Annealing Ambients on the Electrical Properties of TiO₂ Thin Films by Metalorganic Chemical Vapor Deposition

Abstract

In this work, we investigate the effects of the top electrode materials and annealing ambients on the electrical properties of chemical-vapor-deposited (CVD) TiO 2 films. Experimental results indicate that the leakage current is mainly determined by the work function of electrode materials before sintering. The capacitor with TaN top electrode reveals the least leakage. After 450° C and 800° C sintering in N 2 , owing to its thermal stability, WN is found to be the optimal material for withstanding high-temperature thermal treatment. From the annealing ambient results, N 2 O was more effective than O 2 in reducing leakage current, and furnace annealing in N 2 O ( FN 2 O) produces the smallest leakage. Such a phenomenon is primarily owing to the reduction of oxygen vacancies and carbon concentration in TiO 2 by the atomic oxygen generated by the dissociation of N 2 O during the thermal cycle, thereby improving film quality.