Deep depletion insulated gate field effect transistors

An integrated circuit device comprising:

• an insulating substrate,
• a plurality of thin, layerlike bodies of monocrystalline semiconductive material, all initially of the same given type conductivity on said substrate, and each having a surface substantially parallel to the surface of the substrate, and
• means including at least one of said bodies forming an insulated gate field effect transistor operable in the deep-depletion mode, said means comprising spaced source and drain regions of said given type conductivity in said one body defining therebetween a conduction channel region, an insulating layer on said surface of said one body adjacent to said channel region and gate electrode means on said insulating layer, said channel region having a first part adjacent to said surface having a thickness less than that of said body, having said given type conductivity and having a conductivity such that a predetermined voltage applied to said gate electrode, relative to that applied to said body, will effectively deplete said first part of mobile charge carriers, said channel region also having a second part beneath said first part, extending throughout the remainder of the thickness of said channel region, having said given type conductivity and having a conductivity less than that of said first part such that a voltage substantially less than said predetermined voltage will effectively deplete it of charge carriers.