Resolving the gas adsorption dynamics and its electronic impacts on quasi-2D oxide semiconductors

Tzu Jie Lin^1*

¹college of electrical and computer engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Tzu Jie Lin, email:jay980611@gmail.com

In the past few years, there has been a significant emphasis on atomically-thin metal oxide semiconductors, such as In2O3, driven by their adjustable electrical properties that open up a range of electronic applications. However, the electrical characteristics of oxide semiconductor remain highly unstable as the environment changes. In this work, we elucidate the mechanisms of surface gas adsorption and desorption through various experiments, such as illumination, annealing and stressing tests. Time-resolved electrical measurements conducted in different atmospheric conditions reveal that the variations in threshold voltage (VT) arise from the oxygen adsorption mechanism. UV and X-ray illumination, nitrogen annealing, and negative bias stressing (NBS) induce a negative VT shift, while oxygen annealing and positive bias stressing (PBS) result in a positive VT shift. The modulation of VT shift, which corresponds to sheet carrier density, is comparable to the outcomes achieved through doping techniques employed in other ultrathin transistors and silicon-based transistors. In addition, when the device is removed from the specific environment, its electrical characteristics will gradually revert to the initial values over time. This study highlights the influence of VT on the environment and analyzes the mechanism behind the increase/decrease in oxide semiconductor carrier concentration induced by the methods

Keywords: oxide semiconductors, Indium oxide, ultrathin semiconductor, threshold voltage