Ga0.51In0.49P/In0.15Ga0.85As/GaAs pseudomorphic doped-channel FET with high-current density and high-breakdown voltage

Ga0.51In0.49P/In0.15Ga0.85As/GaAs pseudomorphic doped-channel FET's exhibiting excellent de and microwave characteristics were successfully fabricated, A high peak transconductance of 350 mS/mm, a high gate-drain breakdown voltage of 31 V and a high maximum current density (575 mA/mm) were achieved, These results demonstrate that high transconductance and high breakdown voltage could be attained by using In0.15Ga0.85As and Ga0.15In0.49P as the channel and insulator materials, respectively, We also measured a high-current gain cut-off frequency f(t) of 23.3 GHz and a high maximum oscillation frequency f(max) of 50.8 GHz for a 1-mu m gate length device at 300 K. RF values where higher than those of other works of InGaAs channel pseudomorphic doped-channel FET's (DCFET's), high electron mobility transistors (HEMT's), and heterostructure FET's (HFET's) with the same gate length and were mainly attributed to higher transconductance due to higher mobility, while the de values were comparable with the other works, The above results suggested that Ga0.51In0.49P/In0.15Ga0.85As/GaAs doped-channel FET's were very suitable for microwave high power device application.