Achieving Exceptional Stability in Self‐Aligned Coplanar Amorphous Oxide Thin‐Film Transistors through Hydrogen Scavenger Layer

Amorphous indium–gallium–zinc oxide (a‐IGZO) films, widely used as the active layer in thin‐film transistors (TFTs), require strict control of hydrogen levels for stability. Dehydrogenation processes are employed to reduce hydrogen in the gate insulator and passivation (PAS) layers, preventing its diffusion into the channel. As devices scale down, even low concentrations of hydrogen can significantly impact performance, necessitating ultralow hydrogen levels in the effective channel. Here, a novel technique using the hydrogen scavenger layer (HSL) for blocking and capturing hydrogen from the PAS layer to the channel is reported. The insertion of the HSL not only blocks hydrogen molecules but also absorbs and retains them within the HSL. This induces remarkable enhancement in the qualities of the a‐IGZO films by minimizing the number of hydrogen‐related bonds and improving an exceptionally durable and reliable active layer. As a result, the a‐IGZO TFTs, compared to conventionally structured a‐IGZO TFTs, exhibit improved electrical performances in mobility from 9.87 to 12.91 cm 2 (V −1 s −1 ), active breakdown voltage from 79.2 to 141.8 V, transient current stress from 1.21% to 0.37%, and threshold voltage shift (under positive and negative bias temperature and illumination stress for 11 h at 50 °C) from −73 to −11 mV, and −9.86 to −2.31 V.