Effects of Mg doping on the gate bias and thermal stability of solution-processed InGaZnO thin-film transistors

Abstract

Mg-doped IGZO TFTs showed improved TFT performance and thermal stability due to fewer oxygen deficiencies and less interface electron trapping. • We fabricated Mg-doped IGZO TFTs with improved performance using solution-process. • Mg doping reduced the oxygen deficiencies and less interface electron trapping of a-IGZO films. • Mg dope-TFT showed high mobility of 2.35 cm 2 /V s and an on–off current ratio over 10 6 . • For better device stability (gate-bias and thermal stability) was proved. The effects of magnesium (Mg) doping (molar ratio Mg/Zn = (0–10 at.%)) on solution-processed amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) grown using the sol–gel method are investigated. TFT devices fabricated with Mg-doped films showed an improved field-effect mobility of 2.35 cm 2 /V s and a subthreshold slope (S) of 0.42 V/dec compared to those of an undoped a-IGZO TFT (0.73 cm 2 /V s and 0.74 V/dec, respectively), and an on–off current ratio of over 10 6 . Moreover, the 5 at.% Mg-doped TFT device showed improved gate bias and thermal stability due to fewer oxygen deficiencies, smaller carrier concentration, and less interface electron trapping in the a-IGZO films.