SRH based trap model for GaN MMIC power switches

Gallium Nitride (GaN) HEMTs have increasingly been used in high frequency switching power converters. The combination of high voltage, high current, high temperature and low-on resistance enables higher efficiency and lower form factor as compared to Silicon devices. FET switch operate in the linear ohmic region. However, the presence of trap centres in GaN HEMTs alter the on-resistance and shifts the threshold voltage, causing current collapse and degrades the efficiency. Pulsed I-V measurements of a commercial foundry GaN MMIC HEMT revealed drain current collapse and on-resistance modulation in the ohmic region of the HEMT loadline. A trap model based on SRH theory was used to characterize trapping effects that alter the drain current in the linear region of operation.