Effect of thickness on structure and optoelectrical properties of Ti doped indium tin oxide thin films deposited by RF magnetron sputtering

Titanium-doped indium tin oxide (ITO:Ti) thin films were prepared on glass substrates with various film thicknesses (50-360 nm) by radio frequency (RF) magnetron sputtering using one piece of ceramic target material. The effects of thickness on the structural, surface morphology, electrical and optical properties of ITO:Ti films were investigated by means of X-ray diffraction (XRD), Atomic Force Microscope (AFM), ultraviolet (UV)-visible spectroscopy and electrical measurements. XRD patterns show the highly oriented (400) direction. With the increasing thickness, the crystallization enhances and grain size increases, Meanwhile, the film becomes more dense. As the film thickness increasing, the RMS roughness, average roughness and resistivity of the thin film decreases and then increases. RMS roughness is the lowest when the thickness is 250 nm. The lowest resistivity of the 200 nm thick film is 2.1×10^-3 Ω·cm. The transmittance of different thick film is more than 89% in the visible light range with different thickness.