【International Papers】Ge doping of α-Ga₂O₃ thin films via mist chemical vapor deposition and their application in Schottky barrier diodes

      Researchers from the Kyoto University have published a dissertation titled "Ge doping of α-Ga₂O₃ thin films via mist chemical vapor deposition and their application in Schottky barrier diodes " in Journal of Applied Physics.

ABSTRACT

      We performed Ge doping of α-Ga₂O₃ thin films grown on m-plane sapphire substrates using mist chemical vapor deposition. Although the typical growth rate was high at 4 μm/h, the resultant α-Ga₂O₃ thin films exhibited high crystallinity. We controlled the carrier density in the range of 8.2 × 10¹⁶–1.6 × 10¹⁹ cm⁻³ using bis[2-carboxyethylgermanium(IV)]sesquioxide as the Ge source. The highest mobility achieved was 66 cm² V⁻¹ s⁻¹ at a carrier concentration of 6.3 × 10¹⁷ cm⁻³. Through secondary ion mass spectrometry analysis, a linear relationship between the Ge concentration in the α-Ga₂O₃ thin films and the molar ratio of Ge to Ga in the source solution was established. The quasi-vertical Schottky barrier diode fabricated using the Ge-doped α-Ga₂O₃ thin films exhibited an on-resistance of 7.6 mΩ cm² and a rectification ratio of 10¹⁰. These results highlight the good performance of the fabricated device and the significant potential of Ge-doped α-Ga₂O₃ for power-device applications.

FIG. 1. Schematic structure of the Ge-doped α-Ga₂O₃ thin films for the Hall-effect measurement when the [Ge]/[Ga] molar ratios of the source solution are (a) below and (b) above 10⁻²%. (c) Schematic structure of the SBD based on the Ge-doped α-Ga₂O₃ thin films.

FIG. 2. (a) XRD 2θ/ω scan profiles of the Ge-doped α-Ga₂O₃ thin films. (b) Full width at half maximum (FWHM) value obtained from the ω scan rocking curves corresponding to the α-Ga₂O₃ 303¯0 peak for the thin films with different Ge precursors and varied [Ge]/[Ga] molar ratios in the source solutions.

Original link:https://doi.org/10.1063/5.0207432