Design of high performance normally-off dual junction gate AlGaN/GaN heterostructure field effect transistors for high voltage application

Abstract

In this paper, a novel normally-off dual junction gate AlGaN/GaN heterostructure field effect transistor (DJG-HFET) is proposed for reducing on-resistance, decreasing the subthreshold swing, enhancing threshold voltage and improving the breakdown voltage. The proposed DJG-HFET is simulated by a Lombardi mobility model calibrated by comparing with the experimental results of a p-type gate GaN-based HFET. The on-resistance can be reduced 34% while the on-state current can be increased 40% for common p-type gate GaN based HFETs by inducing a new channel under the gate at $$V_\mathrm{GS}=5 \,\hbox {V}$$ , and the leakage current remains 0.4 nA/mm when $$V_\mathrm{GS}=0\,\hbox {V}$$ and $$V_\mathrm{DS}>600\,\hbox {V}$$ . The breakdown voltage of the proposed device is 910 V, which is 14% higher than that of common p-type gate GaN-based HFETs. The lowest $$R_\mathrm{on}$$ of $$9.8\,\Omega \, \hbox {mm}$$ and the highest $$V_\mathrm{th}$$ of 2 V can be achieved by optimizing the design parameter of $$ D_\mathrm{bg}$$ and $$N_\mathrm{p}$$ .