Investigation of co-sputtered LiZnSnO thin film transistors

We proposed the fabrication of Li–Zn–Sn–O (LZTO) thin film transistors (TFTs) using a magnetron co-sputtering method. To analyze the effects of Li incorporation on the amorphous LZTO TFTs, Hall measurement and X-ray photoelectron spectroscopy were performed. It was found that the increased addition of Li to the ZTO system caused the suppression of carrier creation. At an optimized condition (~ 12 at.% Li) for LZTO TFTs, we achieved a saturation mobility of ~ 10.4 cm2/V s, a subthreshold voltage of 0.25 V/decade, a threshold voltage (Vth) of 3.9 V, and an Ion/off ratio of 2 × 108. Furthermore, the optimized device exhibited much better photo-bias stability (ΔVth = − 3.3 V) than the reference ZTO device (ΔVth = − 10.8 V) under the negative bias illumination stress condition.

► Li doping was first attempted into a ZnSnO (ZTO) film.
► Incorporated Li element acts as an acceptor leading to the reduced carrier density.
► Optimized Li-doped ZTO transistor exhibited the improved electrical performance.