Atomic Layer Deposition for Vertically Integrated ZnO Thin Film Transistors: Toward 3D High Packing Density Thin Film Electronics

We report on the first demonstration of the atomic layer deposition (ALD) based three dimensional (3D) integrated ZnO thin film transistors (TFTs) on rigid substrates. Devices exhibit high on-off ratio (∼106) and high effective mobility (∼11.8 cm2 V−1 s−1). It has also been demonstrated that the steps of fabrication result in readily stable electrical characteristics in TFTs, eliminating the need for post-production steps. These results mark the potential of our fabrication method for the semiconducting metal oxide-based vertical-integrated circuits requiring high packing density and high functionality.