Effect of Metallic Composition on Electrical Properties of Solution-Processed Indium-Gallium-Zinc-Oxide Thin-Film Transistors

We report the combinatorial study on surface morphology and electrical properties of solution-processed amorphous indium-gallium-zinc-oxide (
a
-
IGZO
) thin-film transistors (TFTs). The sol-gel-processed
a
-
IGZO
thin films typically have shown an amorphous structure and critical dependence of mobility, carrier concentration, and surface roughness on the
In, Ga
, and
Zn
molar ratio in the solution phase. Based on efficient control of the metallic components from the sol-gel process, the solution-processed
a
-
IGZO
T FTs with a mobility of 0.5-2 cm
²
/V ·s, on/off current ratio > 10
⁷
, and a subthreshold slope of as steep as 1.5 V/dec were obtained.