An Al₂O₃ AlGaAs/InGaAs metal-oxide-semiconductor phemt spdt switch with low control currents for wireless communication applications

An AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high electron mobility transistor (MOS-PHEMT) single-pole-double-throw (SPDT) switch using Al₂ O₃ high- κ gate dielectric by atomic layer deposition is fabricated. The MOS-PHEMT exhibited a comparable dc performance and a much lower gate current compared to PHEMT. Radio-frequency (rf) test shows that the MOS-PHEMT switch has an insertion loss of less than 0.5 dB, an isolation larger than 30 dB, a return loss larger than 15 dB, and an input power for 1 dB compression of 31.4 dBm at 2.5 GHz. Overall, MOS-PHEMT monolithic microwave integrated circuits switches have comparable rf performance to PHEMT switches but with much lower dc power consumption.