29. Thermal Properties

In this chapter, an overview of the current research progress on the thermal properties of beta-gallium oxide (β-Ga₂O₃) is provided. Thermal properties of β-Ga₂O₃ are of great significance to the device reliability and performance in its potential applications. Previous research through both computational and experimental studies on β-Ga₂O₃ using various methods is reviewed. The most notable findings are the relatively low and highly anisotropic thermal conductivity. At room temperature, the [010] direction has the highest thermal conductivity of around 25 W/mK, while that in the [100] direction is measured to be the lowest, which is around 13 W/mK. We also make comparison between β-Ga₂O₃ and GaN, another widely used semiconductor for power electronics. The relatively low thermal conductivity of β-Ga₂O₃ compared to GaN may present a major challenge for its potential applications. Another important thermal property, heat capacity, of β-Ga₂O₃ at room temperature is measured to be 18.7 J/mol K. On the other hand, the effective thermal conductivity in β-Ga₂O₃ thin film is shown to be larger than other gate oxides, providing a possibility of using it as gate dielectrics in GaN device contacts. The thermal properties discussed in this chapter might be useful for thermal management and design of β-Ga₂O₃ devices.