Influence of post-deposition annealing temperature on structural and electrical properties of TiW contact thin films

This paper presents an effect of annealing temperature on microstructure and electrical properties of TiW contact films deposited on ITO thin film at a room temperature using DC magnetron sputtering system. As-deposited TiW contact films are annealed at 200, 400 and 600 degrees C under vacuum environment. The microstructural properties are investigated using XRD, SEM and AFM. The electrical characteristics are characterized by linear transmission line method (L-TLM). The SEM and XRD investigations show that the TiW contact film is composed of circular grains, and the crystals within the film are oriented in either the (110) or (200) direction. An increase in grain size is observed on annealed TiW contact films compared to as-deposited films as investigated from SEM and AFM analysis. Annealing TiW contact films at 600 degrees C improves their ohmic properties, reducing surface roughness and resulting in a specific contact resistance of 6.25 x 10(-2) ohm cm(2) at room temperature. These contacts are suitable for high-temperature sensor applications.