Microwave power performance comparison between single and dual doped-channel design in AlGaAs/InGaAs HFETs

Single and dual doped-channel AlGaAs/InGaAs FETs (DCFETs) were fabricated, characterized, and compared with each other in terms of dc, rf, and power performance. The dual doped channel design provides a higher current density, and a better linear operation range over a wide gate bias range and frequency. A 1 μm-long gate dual-DCFET operated at 1.9 GHz demonstrates a power-added efficiency of 51.5%, a gain of 19 dB, and an output power density of 305 mW/mm at 2.5 V. This performance suggests that dual doped-channel design is more suitable for linear and high power microwave device applications.