Influence of Different Gate Biases and Gate Lengths on Parasitic Source Access Resistance in AlGaN/GaN Heterostructure FETs

The AlGaN/GaN heterostructure FETs with different gate lengths were fabricated. Under different gate biases or for the devices with different gate lengths, the measured parasitic source access resistance values were different. By the analysis of different scattering mechanisms and polarization charge distribution, it is found that the gate bias and gate length can change the polarization Coulomb field scattering, and then affect the parasitic source access resistance. At last, the systematic scattering theories were adopted and the influence of different gate biases and gate lengths on parasitic source access resistance was further confirmed in theory.