Preparation and electrical characteristics of Li–N co-doped InZnAlO thin film transistors by radio frequency magnetron sputtering

In this paper, amorphous Li–N co-doped InZnAlO (IZAO:(Li, N)) thin film transistors (TFTs) with staggered bottom-gate structure were fabricated on SiO2/Si substrates by radio frequency (RF) magnetron sputtering at room temperature. X-ray diffraction (XRD) pattern revealed that the IZAO:(Li, N) as-deposited film was amorphous. Secondary ion mass spectroscopy (SIMS) indicated that the films had a uniformly distribution of species. The TFTs annealed at 265 °C in nitrogen atmosphere showed the better electrical properties with a high saturation mobility (μSAT) of 45.3 cm2V−1s−1, a low threshold voltage (VTH)of 0.5 V, a low subthreshold swing (SS) of 0.42 V/dec, and a high on/off current ratio (Ion/Ioff) of 5.1 × 108. The threshold voltage shift (ΔVTH) under positive and negative bias stability was 14.5 V and −13.1 V, respectively.