Effects of gate stress evaluated using low frequency noise measurements in GaN on Si HEMTs

Change in the drain and gate current low frequency noise (LFN) spectra of GaN-on-Si high electron mobility transistors (HEMTs) is measured before and after the application of electric field stressing on the gate. Extracted Hooge parameters are found to be consistent with previous research. RTS noise spectra are found to appear superimposed upon the 1/f spectrum after device stress. Time constants of the RTS spectra are characterized over a range of temperatures and voltages. It is found that RTS noise time constants change with In(τrts) ∝ 1/kT allowing trap activation energies to be calculated. Electron trapping mechanisms responsible for the modification of the RTS spectra are discussed in connection with degradation processes induced by field dependent stressing.