Performance modulation of transparent ALD indium oxide films on flexible substrates: transition between metal-like conductor and high performance semiconductor states

Abstract

Indium oxide (InOx) films are grown by atomic layer deposition (ALD) using [1,1,1-trimethyl-N-(trimethylsilyl)-silanaminato]-indium (InCA-1) as the metal precursor and hydrogen peroxide (H2O2) as the oxidant. It is found that the electrical properties of the indium oxide layers strongly depend on the ALD growth temperature. Relatively low electrical resistivity (similar to 10(-4) Omega cm) and high optical transparency (>85%) are obtained at growth temperatures higher than 200 degrees C, which make the indium oxide film suitable for transparent conducting oxide (TCO) applications. On the other hand, at relatively low growth temperatures below 150 degrees C, indium oxide behaves as a transparent semiconducting oxide (TSO). Thin film transistors (TFTs) incorporating this material as the active layer exhibit reasonably high performance with saturation mobility exceeding 10 cm(2) V-1 s(-1) and a threshold voltage near 0 V.