Numerical simulation of local doped barrier layer AlGaN/GaN HEMTs

A GaN HEMT with local doped barrier layer is proposed in this paper. The DC and RF characteristics of the proposed GaN HEMT structure is analyzed by using 2D numerical simulation. The results show that the breakdown voltage is 23% larger than that of the entire doped barrier layer structure due to the extension of depletion layer width between gate and drain electrodes, which reduces the electric field peak value at the right corner of the gate. A theoretical maximum output power density of 16.2 W/mm has been achieved, which is ∼34% larger than that of the entire doped barrier layer structure, and 7% larger than that of the unintentionally doped barrier layer structure. And the RF simulation results show that the proposed GaN HEMT also improved the maximum stable gain (MSG) by 0.8 dB up to 25 GHz due to the decrease of the gate-drain capacitance compared to the unintentionally doped and entire doped barrier layer structures.