Investigation on the relationship between channel resistance and subgap density of states of amorphous InGaZnO thin film transistors

► Modeling and simulation of a-IGZO TFTs using TCAD. ► Extraction of subgap DOS modeling parameters. ► Analysis for relationship between channel resistance and subgap DOS of a-IGZO TFTs. The demand for amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) has increased due to their transparent properties. In this paper, we report on the relationship between the subgap density of states (DOS), field-effect mobility (μFE), and unit channel length resistance (rch) on the electrical properties of a-IGZO TFTs. The three tested structures had the same channel width/length and gate insulator thickness with different gate insulator materials, SiNX, SiOX, and SiOX/SiNX. Compared to TFTs with low subgap DOS levels, TFTs with high subgap DOS levels have low μFE values due to the relatively large rch values.