High-voltage RESURF AlGaN/GaN high electron mobility transistor with back electrode

A novel reduced surface field (RESURF) AlGaN/GaN high electron mobility transistor (HEMT) with back electrode is proposed. The back electrode is electrically grounded and attached to the AlN nucleation layer after the substrate is removed. The back electrode, which attracts the electric field lines at the AlGaN/GaN interface by inducing negative charges, leads to a more uniform horizontal electric field along the channel and, hence, a significant improvement in breakdown voltage. Meanwhile, there is negligible negative impact on the ON-state resistance. Numerical simulation demonstrates a breakdown voltage of 1701 V and an ON-state resistance of 10.45 Ω mm with a gate-drain spacing of 6 μm for the proposed device, compared to a breakdown voltage of 1118 V and an ON-state resistance of 10.34 Ω mm for conventional RESURF AlGaN/GaN HEMT.