고전력 전자기기 응용을 위한 용액 공정 산화물 반도체 박막 트랜지스터의 안정성 향상 연구

Abstract

Vacuum-processed oxide TFTs suffer from instability issues under NBIS (Negative Bias Illumination Stress). However, sol-gel oxide TFTs have the problem of being very unstable with respect to NBS (Negative Bias Stress) even in the absence of illumination. As a result, since a negative threshold voltage shift is observed after negative voltage stress is applied, there is a need to overcome the NBS instability of sol-gel oxide TFTs by forming higher quality films. In this study, we proposed Ga-rich IGO TFT with multi-active layer structure to effectively improve bias stability. As the ratio of Ga in the composition ratio of the IGO compound increased, the threshold voltage appeared in a more positive direction. Through the application of a multi-layer structure, the density of the film increases, further improving the stability of the TFT. Therefore, The single-layer sol-gel IGO TFT showed a Vth shift of -21.77V after voltage stress, but the Vth shift was reduced to -13.32V by using IGO with a high Ga ratio as a Bilayer. These results are expected to contribute to increasing the stability of sol-gel TFTs under NBS.