Electronic Properties of the Interface between Si and TiO2 Deposited at Very Low Temperatures

Uniform TiO2 thin films with a large ε r (up to 86) were prepared at low temperatures (200-400°C) by CVD. The films deposited at 200°C were amorphous and those at high temperatures were polycrystalline structures of anatase. The electronic properties of a TiO2/Si interface were analyzed in detail using metal-insulator-semiconductor structures. The minimum interface state density in the bandgap was as low as 2×1011 cm-2 eV-1, showing the usefulness of the TiO2 films for the gate insulators of MIS diodes. An anomalous behavior of photo-induced current observed for the first time is also presented.