Effects of interfacial layer on submicron GaAs MESFETs characteristics

In this paper, the effects of Schottky barrier interfacial layer on submicron GaAs MESFETs characteristics are discussed. The field dependent mobility, μ_οχ of carriers scattering from the channel into the Schottky barrier gate is evaluated. It is shown that μ_οχ increases significantly for devices that have relatively thicker interfacial layer. The effect of interfacial layer thickness on the device transconductance, output conductance and threshold voltage is evaluated. It is demonstrated that an interfacial layer thicker than 0.5 nm, causes adverse effects on the device output and transfer characteristics by lowering its Schottky barrier height. A plausible explanation for reduced barrier height is given. Based on the proposed explanation, the definition of threshold voltage is modified by incorporating a shift caused by the interfacial layer.