A study on the electrical characteristics of copper phthalocyanine-based OTFTs with ZrTaO as gate dielectric

Copper phthalocyanine-based organic thin-film transistors (OTFTs) using ZrTaO high-k gate dielectric with different Ta contents have been fabricated and characterized. It is found that devices with more Ta incorporated in the dielectric film exhibit better electrical properties such as smaller leakage current density, larger breakdown field strength, smaller sub-threshold slope and larger on/off ratio. The involved mechanism lies in that increasing Ta concentration can reduce the interfacial trap density and increase the formation of Al-O bonds in interfacial layer resulting in better interface properties.