Ohmic contact formation process on low n-type gallium arsenide (GaAs) using indium gallium zinc oxide (IGZO)

•We propose a method to fabricate non-gold Ohmic contact on low n-type GaAs with IGZO.•0.15 A/cm2 on-current and 1.5 on/off-current ratio are achieved in the junction.•InAs and InGaAs formed by this process decrease an electron barrier height.•Traps generated by diffused O atoms also induce a trap-assisted tunneling phenomenon.

Here, an excellent non-gold Ohmic contact on low n-type GaAs is demonstrated by using indium gallium zinc oxide and investigating through time of flight-secondary ion mass spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, J–V measurement, and H [enthalpy], S [entropy], Cp [heat capacity] chemistry simulation. In is diffused through GaAs during annealing and reacts with As, forming InAs and InGaAs phases with lower energy bandgap. As a result, it decreases the electron barrier height, eventually increasing the reverse current. In addition, traps generated by diffused O atoms induce a trap-assisted tunneling phenomenon, increasing generation current and subsequently the reverse current. Therefore, an excellent Ohmic contact with 0.15 A/cm2 on-current density and 1.5 on/off-current ratio is achieved on n-type GaAs.

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