Study of source access resistance at direct current quiescent points for AlGaN/GaN heterostructure field-effect transistors
The AlGaN/GaN heterostructure field-effect transistor (HFET) with 100 nm gate length was fabricated. An improved method is proposed to determine the value of the source access resistance corresponding to each direct current quiescent points in the saturation region of the current-voltage characteristics. The increase in the source access resistance with drain-source current has been studied, taking into account several main scattering mechanisms, including polarization Coulomb field (PCF) scattering, polar-optical-phonon scattering, piezoelectric scattering, and interface roughness scattering. It is found that PCF scattering plays a very important role in the source access resistance of AlGaN/GaN HFETs. The PCF scattering component of source access resistance decreases with the increase in drain-source current.