Electrical characterization of a-InGaZnO thin-film transistors with Cu source/drain electrodes

We analyzed the effects of Cu source/drain (S/D) electrodes on the performance of a-InGaZnO (a-IGZO) thin-film transistors (TFTs). Owing to the Cu migration, the parasitic resistance was as low as 10 Ω cm with small current transfer length. Based on the transfer characteristics, we found that VDS dependent Cu migration creates donor-like deep and tail states in the sub-bandgap region. The feasibility of Cu S/D electrodes for a-IGZO TFTs using inverter circuits indicates that fabrication of high performance circuits is possible by controlling the Cu electro-migration.