The annealing temperature effect on the structure and electrical properties of titanium dioxide (TiO2) film deposited by reactive RF sputtering

Titanium dioxide (TiO₂) thin film is deposited using Reactive Radio Frequency (RF) sputtering on Si (100) wafer and annealed in N₂ for 2 hours at different temperatures i.e. 500°C, 750°C and 1100°C. The TiO₂ peak is characterized using X-ray diffraction (XRD). At 500°C and 750°C, only anatase peak is observed with the grain size of 150.72 nm and 186.51 respectively. As the temperature increase to 1100°C, both anatase and rutile structures start to grow but the grain size is reduced to 67.88 nm. The confirmation of grain and the surface roughness is determined by using atomic force microscopy (AFM). The grain sizes become larger from 66.58 nm to 86.01 nm as the temperature increase from 500°C to 750°C as well as the surface roughness (0.271 nm to 1.201 nm). However, at 1100°C, grain size shows no significant different i.e. 84.41 nm (compared at 750°C) and slightly higher surface roughness of 2.194 nm. Thus, the 1100°C annealing temperature requires to attain rutile structure and the smaller particle size. The electrical properties of TiO₂ film annealed at 1100°C shows small amount of current flow through the device thus will be suitable to be used in biosensor application.