Study of 1/f noise in III-V nitride based MODFETs at low drain bias

Flicker noise in MBE grown III-V nitride MODFETs was characterized from room temperature to 130 K. The voltage noise power spectra, S _V(f), were found to be proportional to 1/f ^γ where γ depends on the device temperature as well as the gate bias. A study of S _V(f) as a function of the biasing condition was conducted in detail and was found to vary as V _G ²/(V _G-V _T) ^β where β is a function of temperature. Analyses of the data showed that the noise originated from thermal activation of carriers to localized states in the channel area. The experimental data indicated that number fluctuations were not a major factor in the observed noise. However, more work is needed to determine if surface mobility fluctuations played a key role in the 1/f noise.