Time: 10:45-11:30，Oct.25, 2023，Wednesday
Prof. Aimin Song
University of Manchester， UK
Oxide semiconductors such as InGaZnO (IGZO) have opened a new era in large-area, flexible and transparent applications. Recent examples include the adoption of oxide semiconductors to replace amorphous silicon in display back-plane drive transistors and the rapid development of oxide 3D DRAMs. Despite the progresses, a bottleneck issue of oxide thin-film transistors (TFTs) is the instability either under bias stress or when used as a current source. Furthermore, the carrier mobility and current driving capability need to be improved. It is a huge challenge to overcome both issues using the conventional device structure and oxide semiconductor materials.
Here, we review our recent work on novel oxide TFTs which show a few desirable properties. Rather than using an ohmic metal contact as the source electrode, a high work-function Schottky source contact enables depletion around the TFT source region. This results in an intrinsic immunity to negative bias illumination stress, no obvious short channel effect, and superb current saturation over a wide range of drain voltage1. The flat saturation current gives rise to an extremely high voltage gain reaching 23,000, which is, to the best of our knowledge, the highest gain ever achieved by a solid-state transistor to date. The threshold voltage is also found to remain stable under different drain voltages, in contrast to standard TFTs, which may be useful in larger-area displays where the drain voltages of the drive TFTs may differ due to line resistance2. Moreover, the depletion provided by the Schottky source electrode allows utilizing semi-metal ITO to replace IGZO as the TFT channel layer, which significantly enhances the carrier mobility and current driving capability3. Other work includes oxide Schottky diodes operating beyond 10 GHz4, oxide TFTs operating beyond 1 GHz5, significantly enhanced carrier mobility by self-assembled monolayer treatment6,7, and CMOS-like oxide-based SRAM and logic circuits8,9.
Professor Aimin Song obtained PhD degree in semiconductor physics in 1995. After fellowships from the Royal Society and Alexander von Humboldt foundation at Glasgow University and Munich University, he went to Lund University as a Guest Lecturer before moving to University of Manchester as a Lecturer in 2002. He was promoted to full Professor of Nanoelectronics in 2006. He published over 200 journal papers and has over 40 patents and patent applications on novel electronic-device concepts. He received a Royal Society Brian Mercer Feasibility Award in 2006 and was awarded a Distinguished Achievement Medal for “Researcher of the Year” of the University of Manchester in 2007. His research has been published in Physical Review Letters, Nature Communications, PNAS, Nano Letters, Advanced Functional Materials, Advanced Electronic Materials, etc, and he has contributed over 90 invited/plenary talks at international conferences.