0.6V threshold voltage thin film transistors with solution processable indium oxide (In₂O₃) Channel and Anodized High-κ Al₂O₃ Dielectric

Abstract

<p>Low-voltage operation and low processing temperature of metal oxide transistors remain a challenge. Commonly metal oxide transistors are fabricated at very high processing temperatures (above 500°C) and their operating voltage is quite high (30-50 V). Here, thin-film transistors (TFT) are reported based upon solution processable indium oxide (In<sub>2</sub>O<sub>3</sub>) and room temperature processed anodized high- κ aluminum oxide (Al<sub>2</sub>O<sub>3</sub>) for gate dielectrics. The In<sub>2</sub>O<sub>3</sub> TFTs operate well below the drain bias (V<sub>ds</sub>) of 3.0 V, with on/off ratio 10<sup>5</sup>, subthreshold swing (SS) 160 mV/dec, hysteresis 0.19 V, and low threshold voltage (V<sub>th</sub>)~0.6 V. The electron mobility (μ) is as high as 3.53 cm<sup>2</sup>/V.s in the saturation regime and normalized transconductance (g<sub>m</sub>) is 75μS/mm. In addition, the detailed capacitance-voltage (C-V) analysis to determine interface trap states density was also investigated. The interface trap density (D<sub>it</sub>) in the oxide/semiconductor interface was quite low, i.e., 0.99 × 10<sup>11</sup> - 2.98 × 10<sup>11</sup> eV<sup>-1</sup>· cm<sup>2</sup>, signifying acceptable compatibility of In<sub>2</sub>O<sub>3</sub> with anodic Al<sub>2</sub>O<sub>3</sub>.</p>