Parasitic source resistance at different temperatures for AlGaN/AlN/GaN heterostructure field-effect transistors

The parasitic source resistance (R_S) of AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) is studied in the temperature range 300-500 K. By using the measured R_S and both capacitance-voltage (C-V) and current-voltage (I-V) characteristics for the fabricated device at 300, 350, 400, 450, and 500 K, it is found that the polarization Coulomb field (PCF) scattering exhibits a significant impact on R_S at the above-mentioned different temperatures. Furthermore, in the AlGaN/AlN/GaN HFETs, the interaction between the additional positive polarization charges underneath the gate contact and the additional negative polarization charges near the source Ohmic contact, which is related to the PCF scattering, is verified during the variable-temperature study of R_S.