High breakdown voltage AlGaN/GaN HEMTs with a dipole layer for microwave power applications

A novel high breakdown voltage AlGaN/GaN high electron mobility transistor with a dipole layer (GaN DL‐HEMT) is proposed in this work. The dipole layer (DL) is formed by AlGaN which is attached to the AlGaN barrier and located in the passivation layer between drain and gate electrodes. DL can improve significantly the breakdown voltage (BV) by modulating the distribution of electric field along the channel. The proposed GaN DL‐HEMT exhibits a high BV of 1130 V, which increased from 496 V of conventional GaN HEMT with gate–drain distance of 5 μm, while on‐state resistance keeps 0.48 Ω.mm and FOM at a high level of 2.67 GW/cm ² is obtained. Meanwhile, the cutoff frequency maintains a large value as high as 32.4 GHz, which increases by 74% compared with GaN with a gate field plate. The novel GaN DL‐HEMT shows great prospects in microwave power applications.