Impact of the Scaling of LGS and LG on the On-State Breakdown Voltage of InAlN/GaN HFETs With Localized Fin Under the Gate Electrode

In this manuscript, we have investigated the impact of the scaling of the gate-source length (LGS) and gate length (LG) on the on-state breakdown voltage (BVon) of metallic-face InAlN/AlN/GaN heterostructure field effect transistors (HFETs) having fin structures only under the gate and those having them stretched from source to drain. The results show that the downscaling of LGS and LG augments the electron velocity in the source-access region. Due to current conservation, the higher carrier velocity in the source-access region for the devices having shorter LGS and LG induces a higher electron density under the gated-channel. From what is theoretically observed, the presence of higher electron density close to the boundary with the velocity saturation region at the drain edge of the gate in devices having shorter LGS and LG does seem to initiate the device breakdown at lower drain voltages, leading to the deterioration of the on-state breakdown voltage.