Characterization and analysis of gate and drain low-frequency noise in AlGaN/GaN HEMTs

The gate and drain low-frequency noise (LFN) characteristics of 0.15×200 μm² AlGaN/GaN HEMTs are reported. The measured gate noise current spectral density is low and insensitive to the applied high reverse bias voltage between the gate and the drain. Typical gate noise level values vary from ∼1.9×10^-19 to ∼3.4×10^-19 (A²/Hz) as the drain voltage increases from 1 V to 12 V (V_G=-5 V) at 10 Hz. The calculated Hooge parameter is ∼5.9×10^-4, which is comparable to traditional III-V FETs. Lorentz noise components were observed when V_DS is higher than 8 V. The peak of Lorentz component moves toward higher frequency when V_DS increases and V_GS decreases. The exponent γ of the 1/f^l was found to reduce from 1. 17 to 1.0 1 when V_DS increases from 8 V to 16 V. The observed trends are discussed in terms of electric field, carrier velocity and trapping-detrapping considerations.