Preparation and electrical properties of N-doped ZnSnO thin film transistors

The preparation and electrical properties of N-doped ZnSnO (ZTO: N) thin film transistor (TFT) with a staggered bottom-gate structure were studied in this paper. ZTO: N thin film, which served as the active layer of the prepared TFT, was deposited on SiO2/p-type Si substrates by radio frequency magnetron sputtering at room temperature. Secondary ion mass spectroscopy (SIMS) analysis results showed all the species (Zn, O, Sn and N) were uniformly distributed in the thin film. X-ray Diffraction (XRD) patterns and scanning electron micrograph (SEM) images indicated that the thin film transformed from amorphous to crystalline states due to annealing. X-ray photoelectron spectra (XPS) proved that the oxygen-related defects in the thin film decreased after annealing. The thin film before and after annealing both showed a good optical transmittance of over 80% in visible light region. The TFT prepared with the thin film exhibited n-channel enhancement mode behavior and showed good electrical properties with a saturation mobility of 41.8 cm2V−1s−1, a threshold voltage of 5.4 V, and an on/off current ratio of 6.5 × 107.