Id–Vd Output Characteristics and Transit-Time Model For Short-Gate Length Ion-Implanted GaAs MESFET Using MATLAB

-Two-dimensional analytical model for optically biased non-self-aligned and self-aligned short channel GaAs MESFETs is developed to show the photo effects on the Id–Vd characteristics. When light radiation having photon energy equal to or greater than the band gap energy of GaAs is allowed to fall, the drain current increases significantly as compared to dark condition due to photoconductive effect in parasitic resistances and photovoltaic effect at the gate Schottky-barrier region This paper presents transit time model for short gate –length ion-implanted GaAs MESFET. The finite transit-time that carriers take to traverse the channel from source to drain is calculated considering the effect of onset of velocity saturation.