Field effect transistor with first and second drain electrodes

Abstract

To enhance a drain current voltage characteristics of a compound semiconductor field effect transistor, an n-GaAs substrate is used. After forming an n.sup.- -GaAs layer and an i-AlGaAs layer successively on the substrate, an n-type transistor is formed on these layers. Subsequently, on the rear side of the n-GaAs substrate, an ohmic electrode is formed, to connect with a drain electrode on a surface side. In the structure, when a drain current is increased, at a drain side electron also flows toward the substrate, so that the current concentration on a drain region is relaxed. Thereby, the drain current voltage characteristics can be improved.