High mobility metal-oxide thin film transistors with IGZO/In<inf>2</inf>O<inf>3</inf> dual-channel structure

High-performance Self-aligned top-gate thin film transistors with dual-channel have been successfully fabricated on glass substrate. The dual-layer channel is composed of In ₂ O ₃ and IGZO layers. The introduction of the In ₂ O ₃ thin layer greatly improves the electrical characteristics of the self-aligned top-gate thin film transistors. In comparison, the dual-channel TFT shows higher filed-effect mobility (34.3cm ² /Vs) than single-layer a-IGZO TFT (10.2cm ² /Vs). Apart from that we obtain an on/off current ratio of 10 ⁶ , a steep subthreshold swing voltage of 0.44V/decade and a threshold voltage of -3.35V. This enhancement can be attributed to the In ₂ O ₃ thin layer which offers a higher carrier concentration, thereby maximizing the charge accumulation, generating high carrier mobility and turning the threshold voltage negative.