Low-Frequency Noise Characterization in GaN HEMTs: Investigation of Deep Levels and Their Physical Properties

In this letter, traps-related dispersion phenomenon of GaN/AlGaN/GaN high electron mobility transistor grown on the SiC substrate is investigated through low-frequency noise measurements. Low-frequency drain noise measurements are performed over the frequency range of 20 Hz-1MHz and for varying chuck temperatures (T
_chuck
) ranging between 25 °C and 125 °C. This letter demonstrates that two prominent deep levels are present in the device-under-test with apparent activation energies (E
_a
) of 0.51 and 0.57 eV, respectively. Moreover, signatures of deep level with E
_a
of 0.57 eV become visible only at higher operating temperatures, due to the fact that traps dispersion occurs at very low frequencies, which is confirmed through TCAD physical simulations.