High-Mobility and Good-Stability Thin-Film Transistors With Scandium-Substituted Indium Oxide Semiconductors

Thin-film transistors (TFTs) with the scandium (Sc) substituted indium oxide (ScxIn1-xO3, ScInO) semiconductor were fabricated by RF magnetron sputtering. The saturation field-effect mobilities for TFTs with the Sc concentrations of 1%, 2%, and 5% were 42.9, 30.8, and 25.4 cm
²
V
^-1
s
^-1
, respectively. Moreover, all the devices exhibited similar electrical stability under positive bias stress, but the TFTs with 5% Sc exhibited much better stability under negative bias stress. Detailed studies showed that the incorporation of Sc atoms had effects of suppressing oxygen vacancy formation and reducing the free carrier concentration, and thus improving the electrical stability.