MES field effect transistor possessing lightly doped drain

摘要

In a MESFET of this invention possessed of an LDD structure, a current control layer possessed of conduction type opposite to that of an active layer is formed below the active layer. In the part of this current control layer underlying a gate electrode, a low impurity concentration region destined to function as a channel region for a transistor is formed. Further, LDD regions are formed at both sides of the channel region. In the current control layer, the part underlying the channel region is kept at a low impurity concentration while the other parts underlying the LDD regions are kept at a higher impurity concentration than the part underlying the channel region. Thus, a MESFET possessed of an improved short channel effect and excellent high frequency characteristics is obtained.