Versatile Contact Engineering on β‐Ga₂O₃ Using EGaIn for Schottky Diodes and MESFET Applications

Beta gallium oxide (β‐Ga 2 O 3 ) has emerged as a promising ultrawide bandgap n‐type semiconductor for large‐area circuit integration and high‐power device applications in the field of 5G and AI technology. However, β‐Ga 2 O 3 has a critical problem in Ohmic contact formation using a traditional metallization method. In this study, a low‐temperature fabrication strategy is successfully demonstrated of an Ohmic contact electrode, employing eutectic gallium indium (EGaIn) liquid metal on β‐Ga 2 O 3 active channel material for Schottky diode circuit and metal semiconductor field effect transistor (MESFET) applications. The selective screen‐printing of Ohmic and rectifying contacts enables monolithic integration of symmetric and asymmetric device architectures, including source/drain electrodes, Schottky diodes, and FETs without additional post‐thermal annealing and etching processes. The β‐Ga 2 O 3 /Au Schottky diodes exhibit good rectifying properties of a current on/off ratio of 10⁷ and an ideality factor (η) of 1.63, while the MESFET devices demonstrate a drain current on/off ratio of ≈3.1 × 10 6 .