Noise Characterization and Modeling of GaN-HEMTs at Cryogenic Temperatures

We report on the noise characterization and modeling of AlGaN/GaN high-electron-mobility transistors (HEMTs) at a cryogenic temperature (CT) of
$\sim 10$
K within the frequency range of 4.5–6.5 GHz. This work is the first model in the literature describing the high-frequency noise behavior of GaN-based HEMTs at CTs using a two-parameter-noise concept. The suggested model, which is based on measured noise figures and scattering parameters, provides the frequency and the bias dependence of the cryogenic noise properties of AlGaN/GaN HEMTs. The noise contributions from the intrinsic device, the parasitic network, and the gate leakage are separately extracted. The contribution of the access network is found in the order of 1 K and increases with the frequency, while the gate leakage has an impact of the order of 0.1 K and increases at low frequency. The model provides a basis for the future design and implementation of GaN-based cryogenic low-noise amplifiers.