0.6V Threshold Voltage Thin Film Transistors With Solution Processable Indium Oxide (In₂O₃) Channel and Anodized High-$\kappa$ 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 (In ₂ O ₃ ) and room temperature processed anodized high-κ aluminum oxide (Al ₂ O ₃ ) for gate dielectrics. The In ₂ O ₃ 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 (V _th ) 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 75 μS/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 × 10 ¹¹ -2.98 × 10 ¹¹ eV ^-1 ·cm ^-2 , signifying acceptable compatibility of In ₂ O ₃ with anodic Al ₂ O ₃ .