High mobility thin film transistors with indium oxide/gallium oxide bi-layer structures

We investigate the transport properties of thin-film transistors using indium oxide (In 2 O 3 )/gallium oxide (Ga 2 O 3 ) bi-layer stacks as the channel material. At low gate bias, we observe the transistor field-effect mobility increases with the film resistivity to μ FE =51.3 cm 2 /Vs and ON/OFF current ratio to 10 8 due to combinatorial layer thickness modulation. With the Ga 2 O 3 layer thickness ratio increase to R=14.35%, these observations are accompanied with one-order-of-magnitude reduction in the transistor subthreshold swing to 0.38 V/decade and suggest a trap-limited conduction mechanism upon which the reduced scattering centers due to annihilation of subgap states improve the device electric characteristics without post-growth annealing.