【Device Papers】Gallium oxide/indium gallium zinc oxide heterojunction Schottky barrier thin-film transistors with ultrahigh 2D electron density over 6 × 10¹³/cm²

      Researchers from the Shanghai Jiao Tong University have published a dissertation titled " Gallium oxide/indium gallium zinc oxide heterojunction Schottky barrier thin-film transistors with ultrahigh 2D electron density over 6 × 10¹³/cm²" in Journal of Vacuum Science & Technology A.

Abstract

      To enhance the current driving capability of oxide semiconductor thin-film transistors (TFTs) is a key challenge in emerging display applications that request high resolution and brightness, such as micro-light-emitting diode. In general, increasing the indium content in indium gallium zinc oxide (IGZO) to achieve high mobility is the most common method, but indium-rich IGZO TFTs suffer from negative threshold voltage (V_TH) and poor stability. In this work, a novel high on-current enhancement-mode Schottky barrier TFT is fabricated through the Ga₂O₃/IGZO heterojunction and Ni/IGZO Schottky junction. A high-density two-dimensional electron gas with sheet carrier density over 6 × 10¹³/cm² is achieved, by introducing an oxygen-vacancy-rich Ga₂O₃/IGZO interface. The sheet carrier density is beyond the gate control limitation, leading to a low channel resistance. The source/drain Schottky junction is achieved through defect engineering by Ga₂O₃ growth and etching at the Ni/IGZO interface. The Schottky barrier can be modulated by gate voltage so that the device can be turned off with a large V_TH of ∼1 V. The proposed Ga₂O₃/IGZO Schottky barrier heterojunction TFT enables a new approach to enhance the current driving capability of oxide TFTs beyond conventional material engineering for high mobility.

DOI：

https://doi.org/10.1116/5.0268479