Electrically stable low voltage ZnO transistors with organic/inorganic nanohybrid dielectrics

Abstract

We report on the fabrication of top-gate ZnO thin-film transistors (TFTs) with organic and inorganic nanohybrid dielectric layers that take superlattice form in their inside structure. The nanohybrid dielectrics were prepared by the alternate deposition of organic self-assembled monolayer and oxide monolayer on sputter-deposited ZnO channel. With a 22-nm-thin AlOx-based hybrid dielectric layer (similar to 130 nFcm(2)), our ZnO TFT showed a field mobility of 0.36 cm(2)V s operating at 8 V, while the mobility increased up to 0.66 cm(2)V s with a 22-nm-thin AlOx-based/TiOx-based/AlOx-based (5.5 nm11 nm5.5 nm and similar to 220 nFcm(2)) triple hybrid layer under 2 V operation. Since both ZnO-TFTs display little gate hysteresis, we conclude that our nanohybrid dielectric approach is promising to achieve a gate-stable low voltage top-gate ZnO-TFTs.