【Epitaxy Papers】The effect of hydrogen annealing on the electrical properties of β-Ga₂O₃/4H-SiC MOSFETs grown by liquid-injection MOCVD

      Researchers from the Slovak Academy of Sciences have published a dissertation titled "The effect of hydrogen annealing on the electrical properties of β-Ga₂O₃/4H-SiC MOSFETs grown by liquid-injection MOCVD" in Materials Science in Semiconductor Processing.

Abstract

      Gallium oxide (Ga₂O₃) is a promising semiconductor material for high-power electronics; however, its low thermal conductivity is a challenge for the device performance and reliability. To address this issue, heteroepitaxial β-Ga₂O₃ thin films were grown on highly-thermally-conductive 4H-SiC substrates using liquid-injection MOCVD and subjected to H-containing annealing at different temperatures to enhance their conductivity. The MOSFET devices processed on Si-doped β-Ga₂O₃ films were annealed at identified optimal temperature of 550 °C, and showed output current of 0.8 mA/mm, ON/OFF current ratio of ∼10⁶, and breakdown voltage of 150 V. Using structural, compositional, and electrical characterization of the films and devices, observed resistivity drop was attributed to H passivation of the compensating acceptor centers, possibly via formation of Ga-vacancy–hydrogen complexes. Low MOSFET output current was proposed to originate from nearest-neighbor hopping conduction with the activation energy of ∼141 meV. We propose the observed transport mechanism is a result of structural disorder introduced by O vacancies or Si-OH complexes. Further, another deeper donor with energy level of ∼69 meV was identified and assigned to Si atom occupying octahedrally-coordinated Ga site.

DOI：

https://doi.org/10.1016/j.mssp.2025.110402