Three-dimensional thermal analysis of heterogeneously integrated β-Ga₂O₃-on-SiC SBDs using Raman thermography and electrothermal modeling

β-Ga₂O₃, despite its ultra-wide bandgap and excellent electrical properties, requires heterogeneous integration with high thermal conductivity substrates like SiC for high-power electronics applications due to its naturally low thermal conductivity. Accurately characterizing the channel temperature in β-Ga₂O₃-based devices is challenging due to infrared transparency in ultra-wide bandgap semiconductors. Our study employs three-dimensional Raman thermography to investigate the thermal behavior of β-Ga₂O₃-on-SiC (GaOISiC) and β-Ga₂O₃ bulk Schottky barrier diodes (SBDs) at various power levels. The ultrathin β-Ga₂O₃ epilayer enables the extraction of near-junction temperature within the GaOISiC SBD. Moreover, temperature profiles were obtained both laterally across the device channel and depth-wise from the junction to the substrate. The GaOISiC SBD exhibits a thermal resistance of about only one-third that of the β-Ga₂O₃ bulk SBD. An electrothermal model was used to calculate detailed electrical and temperature field distributions and verify the accuracy of the Raman temperature mapping. This work highlights the advantages of Raman thermography combined with electrothermal simulations in the accurate temperature characterization of β-Ga₂O₃-based devices and demonstrates the benefits of heterogeneous integration for substantially improved heat dissipation.