A Performance Comparison Between β -Ga2O3 and GaN HEMTs

We report on the quantitative estimates of various metrics of performance for β-Ga2O3-based high electron mobility transistors (HEMTs) for RF and power applications and compare them with III-nitride devices. Device parameters such as electron velocity and current density are estimated based on an optical phonon model reported earlier. 2-D simulation using an appropriate velocity-field relationship was employed to study the device characteristics and to assess the RF performance. It is found that despite a lower cutoff frequency, β-Ga2O0HEMTs are likely to provide higher RF output power compared to GaN HEMTs in the low-frequency regime. However, the thermal resistance (TR) and the channel temperature of β-Ga2O3HEMTs are expected to be significantly higher than those of GaN HEMTs which will pose serious limitations on heat dissipation. β-Ga2O3modulation doped field effect transistor on extremely thinned substrates will have similar TR s as compared to GaN devices on GaN substrates. The cutoff frequency was found to drop by 50% as the power dissipation increases from 1 to 7 W/mm. On the other hand, for estimates of dc power switching performance, we estimate the net losses as a function of device periphery and find that~ 8×-10× lower electron mobility in Ga2O3devices compared to that in AlGaN/GaN HEMTs will limit its dc switching as well as its ONstate performance in terms of efficiency, loss, and current carrying capability although the blocking voltage can be much higher than in GaN.