| 摘要 |
A field effect transistor of the present invention includes a semiconductor substrate, an active layer formed by doping an impurity in a surface region of the semiconductor substrate, two heavily doped layers formed respectively by doping the impurity at the two end portions of the active layer, a gate electrode formed on the active layer to be in Schottky contact with the active layer, and source and drain electrodes formed respectively on the two heavily doped layers to be in ohmic contact with the two heavily doped layers. The length WC of a portion where a gate-electrode-side portion of at least one of said source and drain electrodes and said heavily doped layer overlap each other is set with respect to a length WG of a portion where at least one of source- and drain-electrode-side edge portions of said gate electrode and said active layer overlap each other to satisfy 1¢.mu.m! + WG < WC < 5WG. For this reason, a drain current flowing in the gate-electrode-side edge portion of the source or drain electrode is distributed as compared to the prior art, thereby reducing the contact resistance of the source or drain electrode. Therefore, since the drain-source resistance in an ON state is reduced, the field effect transistor can he applied to a circuit which requires a high breakdown voltage as needed.
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