Microwave Power Performance of AlGaN/GaN High‐Electron‐Mobility Transistor on Semi‐Insulating Mn‐Doped GaN Substrate

Herein, a DC and microwave performance of 2 μm gate length AlGaN/GaN high‐electron‐mobility transistor (HEMTs) on a Mn‐doped GaN substrate is demonstrated. The maximum drain current is 670 mA with a threshold voltage of 2.5 V and with good pinch‐off characteristics. The breakdown voltage of the HEMT is ≈80 V. The HEMT shows Δ8% current collapse while referenced HEMT on a SiC substrates which is fabricated simultaneously shows large Δ30% current collapse. When the HEMT with a gate width of 100 μm is tuned for the maximum output power at 2.4 GHz with a drain voltage of 30 V, it delivers 500 mW (5 W mm⁻¹) with the maximum drain efficiency of 54%. These output performances are in good agreement with ideal class‐A operation performance. Therefore, it is concluded that the HEMT on Mn‐doped GaN substrates is promising for future microwave and millimeter‐wave high‐power transistors.