Enhancing oxide semiconductor channel performance through heterojunction engineering of indium–tungsten oxide and indium–gallium–zinc oxide

Abstract We demonstrate enhanced stability and mobility in thin-film transistor (TFT) operation by integrating indium–tungsten oxide (IWO) with the widely used indium–gallium–zinc oxide (IGZO) channel. Comprehensive electrical analyses of single thin films and various heterojunction structures using IGZO (1:1:1, 4:2:4.1) and IWO channels provide valuable insights into mobility characteristics and stability under positive gate bias stress (PGBS) for amorphous oxide semiconductor heterojunction engineering. In particular, the mechanism analysis based on VG-mobility characteristics is explained in detail, considering the strength of the built-in electric field according to the differences in the potential wells at the IWO/IGZO (1:1:1) and IWO/IGZO (4:2:4.1) junction interfaces. Consequently, the IWO/IGZO (1:1:1) heterojunction channel exhibited significantly enhanced mobility compared to the single IGZO (1:1:1) channel and demonstrated the highest PGBS stability among all proposed channel structures in the manuscript. The developed IWO front-type heterojunction channel seems promising for TFT-based applications that require excellent stability and enhanced mobility.