Majority charge carrier bipolar diode with fully depleted barrier region at zero bias

A semiconductor device comprising a semiconductor body including first and second semiconductor regions of one conductivity type separated by a barrier region having a net activator concentration of the opposite conductivity type, means for providing a current path in said body between said first and second regions across said barrier regions, the current flow through said barrier region being by charge carriers of said one conductivity type, said first region having a higher doping concentration of the one conductivity type than the second region, said barrier region being sufficiently thin that the depletion layers formed at zero bias with both said first and second regions merge together in said barrier region to substantially deplete at zero bias the whole of said barrier region of mobile charge carriers of both said one and opposite conductivity types.