Channel Properties of Ga₂O₃-on-SiC MOSFETs

We report the characterization of the channel mobility properties of metal-oxide-semiconductor fieldeffect transistors (MOSFETs) on the heterogeneous β-Ga ₂ O ₃ -on-SiC (GaOSiC) substrate fabricated by an ion-cutting process. The mobility of GaOSiC MOSFETs is significantly improved as the postannealing temperature of Ga ₂ O ₃ channel increases from 900 °C to 1200 °C. The GaOSiC transistor annealed at 1200 °C exhibits mobility consistent with the β-Ga ₂ O ₃ donor wafer, which suggests that the defects in Ga ₂ O ₃ channel induced by the H ⁺ implantation for the ion-cutting step can be eliminated by the high-temperature annealing. As the ambient temperature (T _amb ) increases from 0 °C to 150 °C, the mobility within the accumulation regime of GaOSiC MOSFETs decreases with the temperature following a T ^-1 amb law, which is limited by the phonon scattering. The results of this work will be critically important for designing the transport properties of the GaOSiC channel, significantly advancing the development of Ga ₂ O ₃ power devices on high thermal conductivity substrate.