T-CAD simulations study on drain leakage current and its correlation with gate current for AlGaN/GaN HEMTs

The electrical measurements, performed on devices under test, showed a high Delta Vth between the I-d/V-g curves at different V-d and a high Delta I-g; therefore, we started a simulation study in order to understand which physical parameters impact the drain current in subthreshold condition and consequently the gate current. One of these parameters turned out to be the traps concentration inside buffer layer and therefore the role of epitaxy in the active part of the device. Technology-Computer Aided Design (T-CAD) numerical simulations have been carried out, taking into account the tunneling effect under the Schottky gate. Different traps concentrations were investigated, and this analysis gives a good starting point for the epitaxy optimization especially linked to active part of the device.