Impacts of substrate heating schemes on characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs fabricated on flexible substrates

The impacts of substrate heating scheme on the characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs fabricated on flexible PEN substrate are investigated. For the a-IGZO TFTs fabrication, the substrate is heated during the a-IGZO deposition, pre-annealing in N
2
is also conducted before passivation layer deposition, and post-annealing is done at last. The results show that the pre-annealing and post-annealing improve the hysteresis characteristics, but degrade the field-effect mobility μ
FE
and subthreshold swing SS. In contrast, both the hysteresis voltage V
h
and the electrical performance are enhanced when the a-IGZO is sputtered with substrate temperature of 150 °C. The major performance parameters μ
FE
, SS, and V
h
are 7.34 cm
²
/Vs, 0.438 V/dec, and 2.3 V, respectively.