9.1: Effect of Nitrogen Doping Content on Electrical Properties and Stability of a‐IGZO TFT

Abstract

To improve the electrical properties and stability of thin‐film transistor (TFT) based on the indium gallium zinc oxide (IGZO) channel, the effect of nitrogen‐doping content on the electrical properties of IGZO films and the IGZO TFT were evaluated. It is found that the mobility and carrier concentration of IGZO films gradually decreases ( μ from 18.11 to 11.25 cm2/ V.s, n from 1.76×107 to 4.38×107 cm‐3 ) with the increase of N2 flow content (0‐8sccm). N‐doping can evidently improve the positive bias stress(PBS) stability of IGZO TFT. Typically, the low‐content N‐doping (1 sccm) can significantly boost the stability of IGZO:N TFT (ΔVth = 3.3 V vs ΔVth=9.54 V for the undoped counterpart), while the electrical properties is at almost no degradation with the mobility and on‐off current ratio (Ion/Ioff)as high as 16.59 cm2 /V.s and 3.55×107, and the sub‐threshold swing (SS) and threshold voltage (Vth) as low as 0.32 V/dec and 1.49 V, respectively. These outstanding reliability performance indicates that the N‐doping with appropriate low‐content is a facile and economical way to improve the electrical properties and stability of IGZO TFT.