Using eutectic gallium indium (eGaIn), a room-temperature liquid-metal alloy, we fabricated ultrathin In2O3 field-effect transistor (FET) devices without the need for electron-beam physical vapor deposition. A drop (~ 10 uL) of eGaIn was placed on the photolithography patterned Si wafer. Eutectic gallium indium was simply then spread onto the surface.The eGaIn coated wafer was briefly immersed in a vertical manner in an ultrasonic bath, of acetone; the removal of the protective coating of photoresist in an ultrasonic bath of acetone leaves behind patterned liquid metal contacts. The low work function of eGaIn reduces the Schottky barrier at the In2O3/eGaIn junction relative to In2O3 with Au or Ag contacts. The native gallium oxide provides excellent wetting and matches the electronic structure of the functional indium oxide closely. Incorporation of liquid metal contacts into device architectures is a step towards developing soft, flexible, sensors for high-throughput point-of-care screening and diagnosis. By using this liquid metal alloy, we can simplify the fabrication process, significantly reducing device processing time and cost of production for transistor-based devices.

Advantages of gallium indium eutectic contacts for In2O3 field-effect transistors

2019 Fall National Meeting

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