ABSTRACT
We fabricated 1 × 240μm2 GaAs MESFET's and investigated their microwave characteristics under optical illumination with varying optical power density from 1.6mW/cm2 to 472mW/cm2. Typical current gain cut-off frequency(fT ) and maximum frequency of oscillation(fmax ) of fabricated devices were 6.6GHz and 13.6GHz, respectively, at Vds =3.0V and Vgs =-0.25V without optical illumination. Under 157mW/cm2 of optical illumination at the same bias, however, fT and fmax were increased to 9.5GHz and 15.3GHz, respectively. Extracted device parasitics with optical illumination are also reported.
