【International Papers】Epitaxial κ-Ga₂O₃/GaN heterostructures for high-electron mobility transistors

      Gallium nitride-based high electron mobility transistors have very important applications in the field of power devices. After more than 20 years of research, gallium / gallium nitride-based high electron mobility transistors (HEMTs) have made significant progress, but the performance of HEMTs is still limited. Recently, Ha Young Kang’s research team from Pukyong National University in South Korea and Geonwook Yoo’s research team from Soongsil University in South Korea, proposed a strategy to combine the polar gate dielectric with GaN HEMTs to improve the sheet resistance of two-dimensional electron gas channels and the field distribution between the gate-drain electrodes. The study effectively improve the performance of HEMT by epitaxial growth of κ-Ga₂O₃ on Al_0.26Ga_0.74N/GaN HEMTs as a single crystal gate medium. Compared to reference devices using amorphous Al₂O₃ as a gate dielectric, the κ-Ga₂O₃-HEMTs device exhibits even more excellent electrical properties. This work reveals the intrinsic polarization properties of κ-Ga₂O₃, proving that the combination of κ-Ga₂O₃ with nitride can effectively improve its electrical properties. The related results was published on Materials Today Physics, titled “Epitaxial κ-Ga₂O₃/GaN heterostructure for high electron-mobility transistors”.

Abstract

      In recent years, significant progress has been made in gallium nitride power supply technology, especially gallium / nitride-based high electron mobility transistors (HEMTs). However, the performance of HEMTs is still limited due to the balance of on resistance and breakdown voltage. Integrating the polar gate dielectric with GaN HEMTs can effectively improve the field distribution between the sheet resistance of two-dimensional electron gas channels and the field distribution between the gate-drain electrodes. Orthogonal forms of κ-Ga₂O₃ has a strong polarity and high dielectric properties if growing epitaxial on GaN. Successfully integrating crystallineκ-Ga₂O₃ on GaN HEMTs, compared to the reference device with an amorphous Al₂O₃ gate medium, the channel sheet resistance decreases by 20% and the cut-off frequency increases from 4.8 GHz to 9.1 GHz. Furthermore, The dielectric properties of theκ-Ga₂O₃ increased the breakdown voltage from 354 V to 380 V by reducing the peak electric field in the gate-drain region.

Paper Link：DOI: 10.1016/j.mtphys.2023.101002