Abstract

This paper deals with the carrier’s transport mode involved in AlGaN/GaN HEMT grown on sapphire substrate according to biasing conditions. Low frequency noise measurements on the drain current source are found to be closely related to the path of the carriers occurring in the two dimensions electron gas (2DEG) and in the AlGaN layer: thus a correlation is found between the 1/f γ frequency index γ and the biasing condition of the device. Physical modelling is used in order to corroborate the γ dependence with the transport mechanism of the carriers, thanks to DC simulations and energetic band diagrams analysis.