Characterization and Modeling of RF GaN Switches Accounting for Trap-Induced Degradation Under Operating Regimes

This paper describes the performance degradation of RF GaN-on-SiC HEMT switches due to the charge trapping, which is triggered by high voltages under operating regimes. A custom measurement setup is used for the characterization of the switching behavior under dynamic control and blocking voltages. It is shown that both small- [i.e., insertion loss (IL)] and large-signal (LS) performances (i.e., switch compression) are affected by traps. Depending on the applied voltages, an increase of the switch IL up to 50% and significant degradation of the switch compression characteristic were measured for a 4 x 75 μm² RF switch in 0.25-μm GaN-on-SiC technology. These mechanisms cannot be observed with conventional static characterization, and they are not described by standard RF switch models. A device model capable to account for the observed characteristics is identified and empirically validated under LS conditions at 10 GHz.