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

Abstract

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 (In2O3) and room temperature processed anodized high- κ aluminum oxide (Al2O3) for gate dielectrics. The In2O3 TFTs operate well below the drain bias (Vds) of 3.0 V, with on/off ratio 105, subthreshold swing (SS) 160 mV/dec, hysteresis 0.19 V, and low threshold voltage (Vth)~0.6 V. The electron mobility (μ) is as high as 3.53 cm2/V.s in the saturation regime and normalized transconductance (gm) 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 (Dit) in the oxide/semiconductor interface was quite low, i.e., 0.99 × 1011 - 2.98 × 1011 eV-1· cm2, signifying acceptable compatibility of In2O3 with anodic Al2O3.