Oxide TFT Array Substrate With Gradient Doping for Mobility Stability

The patent applies local quality by creating a non-uniform distribution of modified metal elements within the oxide semiconductor layer. The concentration of modified metal elements gradually decreases from the gate electrode interface toward the oxide semiconductor layer, forming distinct regions with different compositions. This gradient structure optimizes local electrical properties: the region near the gate electrode benefits from higher modified metal content for enhanced mobility, while regions farther away maintain stability, thus resolving the contradiction between mobility and stability.

The patent applies parameter changes by systematically varying the concentration of modified metal elements as a gradient parameter throughout the oxide semiconductor layer. Instead of maintaining a constant uniform composition, the modified metal element concentration is changed continuously from high near the gate electrode to low in the bulk oxide semiconductor layer. This parameter variation enables optimization of both mobility (enhanced by higher modified metal content at the interface) and stability (maintained by lower modified metal content in the bulk), while still being achievable through controlled manufacturing processes like sputtering with gradient targets or sequential deposition.