A new device structure is introduced which facilitates the production of monolithic bidirectional switches. Astonishingly enough, the diverse demands on the characteristics can be completely realized by intrinsic silicon exhibiting the only doped zones to form ohmic contacts. Emitters are formed by accumulation layers which are caused by a suited potential on MOS-gate electrodes. This allows to invert the type of charge carriers as is required for bidirectional operation. The emitter regions are proposed as tiny mesas of 0.3 mu m width and 1.0 mu m height covering about 6% of both the surfaces. Thus, the structure appears rather simple, but its production requires fine line resolution and processing on both the surfaces of the wafer.