Patent ID: 6940127

Claim:
A semiconductor integrated circuit device comprising: a compound semiconductor layer composed of compound semiconductor; and a MISFET provided on the compound semiconductor layer, wherein the MISFET comprises: an active region provided on the compound semiconductor layer, a gate insulating film formed on the active region, a gate electrode formed on the gate insulating film, and source/drain regions formed on both sides of the gate electrode in the active region, wherein a part interposed between the source/drain regions in the active region is composed by alternately stacking a plurality of first semiconductor layers and a plurality of second semiconductor layers, which contain an impurity for carriers at a high concentration and which film thickness are smaller than the film thickness of the plurality of first semiconductor layers, wherein the plurality of first semiconductor layers and the plurality of second semiconductor layers are made of the same material, and wherein each of the plurality of first semiconductor layers has equal thickness, and each of the plurality of second semiconductor layers has equal thickness.