MOS input protection structure

An input protection device for a V-groove field effect transistor formed in a monolithic semiconductor substrate with a source region therein, base region therein overlying said source, and drain region overlying said base region, at least one V-groove extending into the substrate exposing the base region, an insulative layer overlying the exposed portion of the base region, at least one gate conductor overlying at least a portion of the insulative layer and power supply means connected between said drain and said source through load means, said device comprising

• a planar field effect transistor formed on said substrate and having its own source, its own drain and its own insulated gate electrode,
• signal input means for connecting an input signal to said V-groove transistor, said input means being in electrical interconnection with the source of said planar transistor,
• the drain of said planar transistor being in electrical interconnection with said gate conductor of said V-groove transistor,
• the insulated gate electrode being in electrical interconnection with said power supply means, and
• said source of said planar transistor being formed in said substrate in a manner that defines it as a protective diode at a junction of said source and said substrate and at the same time as an input resistor extending from the region of said insulated gate electrode to said signal input means.