The structural and electrical properties of TiO2 thin films prepared by thermal oxidation

Thin films of TiO2 were grown on n-type Si substrate by thermal oxidation of Ti films deposited by dc sputtering. The phase purity of TiO2 was confirmed by Raman spectroscopy, and secondary ion mass spectroscopy was used to analyze the interfacial and chemical composition of the TiO2 thin films. Metal–oxide–semiconductor capacitors with Al as the top electrode were fabricated to study the electrical properties of the TiO2 films. The current conduction mechanisms in thermally grown TiO2 films were observed to follow the space charge-limited current mechanism followed by a Schottky emission process both at and above room temperature. Three orders of magnitude of reduction in current density were observed for thermally grown samples while measured the I–V characteristics at 77 K and Fowler–Nordheim (F–N) tunneling was found to be a dominant conduction mechanism at higher biasing voltages.