Enhanced Electrical Performance of Amorphous Tungsten-Doped InSnZnO Thin-Film Transistors by Nitrogen Modification

Oxide thin-film transistors (TFTs) are promising candidates for next-generation electronics due to their outstanding electrical performance, low-temperature processing, and good compatibility with semiconductor fabrication processes. However, the trade-offs among electrical parameters limit their overall performance and range of applications. In this study, we enhance the electrical performance of amorphous tungsten-doped InSnZnO (ITZO:W) TFTs through nitrogen modification. By introducing small amounts of nitrogen into the active layer, we effectively passivate interface defects, resulting in a reduced subthreshold swing (SS). As the nitrogen flow rate increases up to 1 SCCM, the density of the interface defect states is reduced to 7.19 × 10 11 cm –2 . The threshold voltage ( V TH ) exhibits a positive shift, while the mobility does not change significantly. The optimized TFT demonstrates superior electrical performance with a high saturation mobility of 42.48 ± 1.99 cm 2 /V·s, a V TH of −1.30 ± 1.59 V, an SS of 0.46 ± 0.08 V/dec, an on/off current ratio of more than 10 8, an off-state current of below 10 –12 A, and enhanced negative bias stress stability with a reduced V TH shift (Δ V TH ). We also investigate the long-term stability of the ITZO:W TFT aging in air. This work demonstrates that ITZO:W TFTs exhibit promising potential for future electronic applications.