Quasi‐Dual‐Channel Oxide Transistors With Enhanced Stability and Performance

ABSTRACT Metal oxide thin‐film transistors (MO TFTs) have emerged as promising candidates for next‐generation displays owing to their high electron mobility and excellent optical transparency. However, device stability depends heavily on the oxygen content: an excess results in poor positive bias stress (PBS) stability, whereas a deficiency leads to degraded negative bias stress (NBS) stability. This sensitivity makes precise control of oxygen content critical, but significantly narrows the processing window. This study introduces a quasi‐dual channel strategy to overcome the issue. The proposed TFTs are composed of a channel layer of oxygen‐rich tantalum‐doped tin oxide (TTO) and an insulator layer of HfO _x with an oxygen‐deficient surface. Compared to conventional TTO/SiO ₂ TFTs, the device exhibits significantly reduced threshold voltage shifts under PBS and NBS, decreasing from 8.82 and −1.07 V to 0.09 and −0.11 V, respectively. In addition, a 4.4‐fold enhancement in mobility was achieved. This quasi‐dual channel design holds promise for general application in oxide TFTs, enabling improved process tolerance.