A Performance Comparison Between β-Ga2O3 and GaN HEMTs

We report on the quantitative estimates of various metrics of performance for beta-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 relationshipwas employed to study the device characteristics and to assess the RF performance. It is found that despite a lower cutoff frequency, beta-Ga2O0 HEMTs 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 beta-Ga2O3 HEMTs are expected to be significantly higher than those of GaN HEMTs which will pose serious limitations on heat dissipation. beta-Ga2O3 modulation 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 similar to 8x-10x lower electron mobility in Ga2O3 devices compared to that in AlGaN/GaN HEMTs will limit its dc switching as well as its ON-state performance in terms of efficiency, loss, and current carrying capability although the blocking voltage can be much higher than in GaN.