AbstractsComputer Science

The aim of the research undertaken for this thesis was to develop a new high-performance amorphous oxide semiconductor (AOS) for use as a channel layer in a thin-film transistor (TFT). AOS TFTs offer higher electron mobility than the established amorphous silicon based technology. A new channel material comprised of aluminum indium tin oxide (AITO) was designed and thin films were deposited via sputtering. AITO thin films have an excellent amorphous phase stability up to 725 °C. The effect of using ultra-thin channel layers was investigated. The turn-on voltage V[subscript ON] tends to strongly increase below a channel thickness of ~12 nm, allowing for the realization of enhancement-mode TFTs. Enhancement-mode TFTs with a channel thickness of 5-10 nm and a mobility of µ[subscript FE] = 15 - 18 cm²V⁻¹s⁻¹, drain current on-to-off ratio of I[superscript ON/OFF][subscript D] = 10⁷, and a sub-threshold swing of S = 0.2 V/dec were achieved.