TeO₂: A Prospective High-k Dielectric

Herein, high-k dielectric behavior of TeO2 thin films is investigated. The films are prepared using pulsed laser deposition on indium tin oxide (ITO)-glass substrates. Increasing the growth temperature has improved the surface roughness, transparency, and bandgap of the films. Films grown at 500 degrees C display nanocrystalline nature which is reflected in the increase of bandgap to 4.7 eV and is higher than the bulk value of alpha-TeO2 (3.7 eV). The nanocrystalline TeO2 films in the metal-insulator-metal configuration show a stable high permittivity of similar to 19 with low leakage current (J < 1 x 10(-7) A cm(-2)) and good voltage stability (alpha = 509 ppm V-2). Field-effect modulation is observed in the metal-oxide-semiconductor stack configuration with tellurium as a semiconductor. The study suggests nanocrystalline TeO2 as a low-temperature processable high-k material with high transparency for transistor applications.