Simultaneous low-frequency noise characterization of gate and drain currents in AlGaN/GaN high electron mobility transistors

摘要

Room temperature low frequency noise characteristics of gate and drain currents of an AlGaN/GaN high electron mobility transistor are reported. A Hooge parameter (α_H) ranging from 10~(-3) to 10~(-4) is extracted for drain current noise as a function of sheet carrier density. Gate current noise is simultaneously measured with drain noise both in the time and frequency domain. A weak correlation is seen between the drain and gate noise. Temporally unstable Lorentzian components on top of stable 1/f~γ noise are observed in the gate noise spectra which also show up as random telegraph signal noise in the time domain. It is proposed that the gate Schottky contact is of high quality but that electrically unstable point defects in the AlGaN layer are the cause of Lorentzians and random telegraph switching noise.