High-performance Ingazno Thin-film Transistors With High-k Amorphous Ba_(0.5)sr_(0.5)ti0_3 Gate Insulator

摘要

We report on high-performance n-channel thin-film transistors (TFTs) fabricated using amorphous indium gallium zinc oxide (a-IGZO) and amorphous Ba_(0.5)Sr_(0.5)TiO_3 (a-BST) as the channel and gate dielectric layers, respectively. a-BST/a-IGZO TFTs achieve low-voltage operation with a high saturation mobility value of 10 ± 1 cm~2/V s, excellent subthreshold slopes of 0.06 ±0.01 V/decade, a low threshold voltage of 0.5 ± 0.1 V, and a high on-off current ratio up to 8×10~7 (W/L = 1000 μm/5 μm) at 3 V. The high capacitance density of a-BST (145 ± 2 nF/cm_2) and the small contact resistance, smaller than the channel resistance, are responsible for the high performance of these TFTs.