Electrical Stability Modeling Based on Surface Potential for a-InGaZnO TFTs under Positive-Bias Stress and Light Illumination

Xiaoming Huang; Wei Cao; Chenyang Huang; Chen Chen; Zheng Shi; Weizong Xu

doi:10.3390/mi14040842

Electrical Stability Modeling Based on Surface Potential for a-InGaZnO TFTs under Positive-Bias Stress and Light Illumination

Micromachines (Basel). 2023 Apr 13;14(4):842. doi: 10.3390/mi14040842.

Authors

Xiaoming Huang¹, Wei Cao¹, Chenyang Huang¹, Chen Chen¹, Zheng Shi², Weizong Xu³

Affiliations

¹ College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
² School of Communications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
³ National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.

Abstract

In this work, an electrical stability model based on surface potential is presented for amorphous In-Ga-Zn-O (a-IGZO) thin film transistors (TFTs) under positive-gate-bias stress (PBS) and light stress. In this model, the sub-gap density of states (DOSs) are depicted by exponential band tails and Gaussian deep states within the band gap of a-IGZO. Meanwhile, the surface potential solution is developed with the stretched exponential distribution relationship between the created defects and PBS time, and the Boltzmann distribution relationship between the generated traps and incident photon energy, respectively. The proposed model is verified using both the calculation results and experimental data of a-IGZO TFTs with various distribution of DOSs, and a consistent and accurate expression of the evolution of transfer curves is achieved under PBS and light illumination.

Keywords: a-IGZO TFTs; electrical stability model; sub-gap density of states; surface potential.

Grants and funding

This research was funded by the National Natural Science Foundation of China (grant no. 61904086 and 62274096) and China Postdoctoral Science Foundation (grant no. SBH19006).