Hiroto Matsubayashi

Analysis of Gate Lag in GaAs Metal-Semiconductor Field-Effect Transistor Using Light Illumination

We have developed a novel method for analyzing the gate lag effect in gallium arsenide (GaAs) metal-semiconductor field-effect transistor (MESFET) using light illumination. It is estimated that the density of trapped electrons at the surface of an active channel layer is above 6×1011 cm-2 from the dependence on photon flux density. Photon energy dependence shows that the electrons are mainly trapped at the GaAs surface. Angle-resolved analysis indicates that the trapped electrons at the active channel layer between the gate and the drain mostly account for the gate lag effect. Temperature dependence of the transconductance (g m) dispersion shows that the activation energy of this trap is 0.33 eV. Two-dimensional device simulation demonstrates the similar transient characteristics of the drain current, which originates from the electrons trapped at the GaAs surface.