Photo-Activated Indium-Strontium-Zinc-Oxide Thin-Film Transistors Using a Strontium Nitrate Precursor

Abstract

Photochemically activated indium-strontium-zinc oxide (ISZO) thin-film transistors ( TFTs) are fabricated by using strontium nitrate as a metallic precursor. The formulated ISZO precursor solutions had a broad absorption characteristic in the ultraviolet region as compared to the IGZO precursor solution. Photochemical activation, which is mediated by deep ultraviolet irradiation in N-2 atmosphere, allowed formation of a dense ISZO and ISO semiconductor films at a low temperature. By optimizing the incorporated strontium composition, ISZO TFTs with an average field-effect mobility of 2.15 cm(2)/Vs, on/off ratio of similar to 10(7), and subthreshold slope of 0.71 V/decade were obtained. In addition, we investigated the positive gate-bias stress characteristics of the ISZO TFTs. The fabricated ISZO TFTs exhibited a positive threshold voltage shift similar to that of IGZO TFTs.