To obtain high-quality n-type doped β-Ga₂O₃ films, silane was used as an n-type dopant to grow Si-doped β-Ga₂O₃ films on (100) β-Ga₂O₃ substrates by metal-organic chemical vapor deposition (MOCVD). The electron concentrations of the Si-doped β-Ga₂O₃ films obtained through experiments can be stably controlled in the range of 6.5 × 10¹⁶ cm⁻³ to 2.6 × 10¹⁹ cm⁻³, and the ionization energy of Si donors is about 30 meV, as determined by analysis and calculation. The full width at half maxima of the rocking curves of the (400) crystal plane of all doped films was less than 500 arcsec, thus showing high crystal quality, while the increase of the doping concentration increased the defect density in the β-Ga₂O₃ films, which had an adverse effect on the crystal quality and surface morphology of the films. Compared with heteroepitaxial Si-doped β-Ga₂O₃ films, homoepitaxial Si-doped β-Ga₂O₃ films exhibited higher quality, lower defect density, and more stable electron concentration, which make them more conductive for preparing Ga₂O₃-based power devices.

The homoepitaxial Si-doped Ga₂O₃ film prepared by metal–organic chemical vapor deposition (MOCVD) was reported in this paper. The film thickness reached 4.5 microns, a relatively high value for MOCVD. The full width at half maxima of the (002) diffraction plane of the film was 26.3 arcsec, thus showing high crystalline quality. The film showed n⁻-type properties with a doping concentration of 3.6 × 10¹⁶ cm⁻³ and electron mobility of 137 cm²/V·s. In addition, the element composition and stress state of the film were characterized and analyzed. This indicates that the MOCVD, supporting high-quality, high-precision epitaxy, is promising for Ga₂O₃ power devices.

In this article, we reported on a Ga₂O₃-based Schottky barrier diode and heterojunction diode from MOCVD. The Si-doped n-type Ga₂O₃ drift layer, grown by MOCVD, exhibited high crystal quality, flat surfaces, and uniform doping. The distribution of unintentional impurities in the films was studied. Then nickel Schottky barrier diode and p-NiO/n-Ga₂O₃ heterojunction diode were fabricated and measured. Without any electric field management structure, the Schottky barrier diode and heterojunction diode have specific resistances of 3.0 mΩ·cm² and 6.2 mΩ·cm², breakdown voltages of 380 V and 740 V, thus yielding power figures of merit of 48 MW·cm⁻² and 88 MW·cm⁻², respectively. Besides, both devices exhibit a current on/off ratio of more than 10¹⁰. This shows the prospect of MOCVD in power device manufacture.