High performance 0.5 μm GaAs MESFET for MMIC applications

Epitaxial and implanted GaAs MESFET devices fabricated with 0.5 μm gate lengths are presented. From d.c. measurements, very high transconductances, respectively equal to 500 mS/mm and 354 mS/mm, are achieved. In each cases, average current gain cut-off frequency Ft of 42.6 GHz and 35 GHz are calculated from S-parameters measurements. The best device exhibit a Ft value of 47 GHz associated with a maximum available cut-off frequency Fmax greater than 98 GHz. These results demonstrate the high performance of 0.5 μm GaAs MESFET for millimeter integrated circuits.