Thermal performance of a thermoelectric-microchannel hybrid cooling system for β-Ga2O3 Schottky barrier diodes using thermoreflectance imaging

The self-heating effect induced by the intrinsically ultralow thermal conductivity of β -Ga 2 O 3 materials severely limits the output performance of β -Ga 2 O 3 -based devices. This work integrates a micro-thermoelectric cooler (TEC) with microchannels (MCs) heat sink and combines advantages of both to enable efficient thermal management of the β -Ga 2 O 3 Schottky barrier diodes (SBDs), as demonstrated through both numerical analyses and experimental characterization. Thermo-reflectance imaging of junction temperature combined with the thermal resistance analysis reveals that, below a critical heat flux of 565 W/cm 2 , the TEC-MC module exhibits significantly improved thermal management performance compared with the standalone MC modules. The dynamic thermal performance analysis of the TEC-MC module indicates that, within the critical heat flux, the TEC-MC module is capable of effective dynamic thermal management. Further analysis of the micro-TEC interfacial effects on the SBD junction temperature shows that electrical boundary resistance has a stronger impact than thermal boundary resistance. In contrast, the thermal contact resistance affects the junction temperature by twice than that of the electrical contact resistance at a TEC input current of 6 A. In addition, further optimization indicates that a flow rate of 100 ml/min is sufficient to meet the cooling requirement, and the minimum SBD junction temperature is achieved at a TE height of 0.2 mm. Compared with the MC module, employing the TEC-MC module for SBD cooling increases the forward current by 17.5% and reduces the on-voltage by 18.5%. This work demonstrates an efficient thermal management strategy for ultralow thermal conductivity of β -Ga 2 O 3 SBDs utilizing TEC-MC hybrid cooling.