Bandgap, Mobility, Dielectric Constant, and Baliga’s Figure of Merit of 4H-SiC, GaN, and β-Ga₂O₃ from 300 to 620 K

Bandgap, mobility, and dielectric constant are important parameters to measure the properties of an opto-electric semiconductor material. Here, this work evaluates the temperature dependence of these basic parameters of the third-generation wide-bandgap semiconductors including 4H-SiC, GaN, and β-Ga2O3, based on which Baliga’s figure of merit (BFOM = εr × μ × Eg3) is obtained correspondingly. Experimental results indicate that as temperature increases, compared with that of 4H-SiC and GaN, the bandgap of β-Ga2O3 shows an obvious shrinkage due to the strong electron–phonon interaction, but the static dielectric constants of these three semiconductors do not show significant changes in a higher temperature range. At room temperature, the BFOM of 4H-SiC and GaN is more dominant, but as temperature increases, the BFOM of the three materials decreases significantly due to the notable reduction of mobility and bandgap, which finally approaches each other at high temperature. Based on the results achieved, this work is expected to provide reference concerning the basic parameters of the third-generation wide-bandgap semiconductors and the corresponding changes appearing in a higher temperature range (300–620 K).