Analytical Modeling of High-Frequency Noise Including Temperature Effects in GaN HEMTs on High-Resistivity Si Substrates

In this paper, analytical modeling of high-frequency noise was carried out including temperature effects in AlGaN/GaN high electron mobility transistors (HEMTs) on high-resistivity Si substrates over a wide temperature range from -50°C to 200°C. The device´s microwave S-parameters and overall noise parameters, including minimum noise figure (NF_min), equivalent noise resistance (R_n) , and optimum source reflection coefficient (|⌈_opt| and ∠⌈_opt) were measured over the whole temperature range. Its small signal equivalent circuit parameters (ECPs) and internal noise source coefficients (P, R, and C) were extracted at each measurement temperature and their temperature variances were fitted using a quadratic relationship. An analytical model of the overall noise parameters is proposed based on Pucel´s PRC theory. It is compared with two other commonly used analytical models and verified with the measured data, including temperature dependence. The feedback capacitance C_gd was found to be important to accurately simulate all the measured noise parameters over temperature.