Preparation and electrical properties of Ni-doped InZnO thin film transistors

Abstract

In this work, Ni-doped InZnO (IZO: Ni) thin film transistors (TFTs) with staggered bottom-gate structure were fabricated on SiO2/Si substrates by radio frequency (RF) magnetron sputtering, and IZO: Ni thin films severed as active layer, Al electrodes were used as the source and drain electrodes. X-ray Diffraction (XRD) results showed that IZO: Ni film was amorphous structure. Transmittance of the deposited sample was higher than 80% in the visible range. Secondary ion mass spectroscopy (SIMS) exhibited a uniform distribution of all the elements in the film. Field emission scanning electron micrograph (FESEM) and Atom force microscopy (AFM) results revealed that the film had a smooth surface and a root-mean-square (RMS) roughness of 0.225 nm. The TFTs annealed at 265 °C in nitrogen atmosphere showed the excellent electrical performance with a high saturation mobility (μSAT) of 37.2 cm2V−1s−1, a low threshold voltage (VTH) of 2.5 V, a low subthreshold swing (SS) of 0.39 V/dec, and a high on/off current ratio (Ion/Ioff) of 4.1 × 108.