Experimental Characterization of Charge Trapping in GaN HEMTs using LF and RF Measurement Techniques

During the last decades, Gallium Nitride (GaN) has demonstrated top-class performance in terms of power density at RF and microwave frequencies. Nevertheless, dispersive effects due to charge trapping and thermal phenomena are known to substantially influence the dynamic behavior of GaN, impairing classical modeling methods. In this talk, we present various characterization methods for the assessment of charge trapping effects applied to different GaN processes on both silicon carbide and silicon substrates. These include techniques based on pulsed and modulated excitation, current transient spectroscopy, and large-signal methods, which will be described along with custom measurement benches operating at both at low-frequency (LF) and at RF. Behavioral modeling procedures based on these techniques will also be described.