Dynamic on-resistance and tunneling based de-trapping in GaN HEMT

GaN HEMT dynamic on-resistance was measured by the pulsed IV method. Temperature-independent de-trapping was observed in GaN HEMT dynamic on-resistance measurement. Similar results were also observed by Dr. Jesus del Alamo´s group at MIT. The origin of the temperature-independent de-trapping is still unclear. It is speculated by Jesus del Alamo´s group that this temperature-independent de-trapping happens through electrons tunneling from the interface layer to the channel instead of through thermal activation. Our experimental results indicate that electrons tunnel from the interface layer into gate may also be possible, especially for those traps located near the gate. A quantum mechanical model based on Fermi´s Golden rule is developed. The modeling result agrees with the experiment and helps to support our theory of the fast temperature- independent de-trapping process.