Negative bias stress stable PtOx/InGaZnOx Schottky barrier diodes optimized by oxygen annealing.

In this work, bottom-Schottky-structure InGaZnO_x (IGZO) Schottky barrier diodes (SBDs) with sputtered PtO_x anodes were fabricated and annealed in oxygen at different temperatures. Critical parameters and negative bias stress (NBS) stability of SBDs with different annealing temperatures are investigated. With the annealing temperature increases, the barrier height and rectification ratio of the SBDs exhibited a rising-then-declining trend, while the ideality factor slightly increased until 200 °C. The SBDs show up overall reliability except for a leakage current rising trend under light, which can be attributed to free electron generation from the ionized oxygen vacancy. Among all the SBDs, the 175 °C annealed ones exhibited the best overall performance, including a high barrier height of 0.89 eV, an ideality factor of 1.14, and a large rectification ratio of over 10⁸. Compared to the initial SBDs, the annealed ones showed up great improvement in NBS stability except for the 200 °C annealed ones, which was permanently degraded and not able to recover to original states. According to experimental result analysis and IGZO material characteristics, a stability model based on the subgap trap transition from V O 2 + to V_O and new V O 2 + creation was proposed, which applies to both the short-term and long-term NBS tests. The results above demonstrate that oxygen annealing at appropriate temperature is an effective method to improve both device performance and NBS stability for PtO_x–IGZO SBDs. [ABSTRACT FROM AUTHOR]