Abstract: In one embodiment, modifications to the polysilicon gate, body, source, and contact masks of a DMOS process add a source-body monocrystalline gate protection diode under the gate pad by implanting an anode region beneath the gate. The anode is connected to the gate through the gate metal in the pad. In addition to the gate-source diode, there is a connection from the drain to the gate through the anode formed by the body region beneath the gate. This embodiment includes a junction terminating field plate. The field plate creates a protection device similar to a zener diode, but exhibits a current/voltage characteristic similar to a thyristor. A significant feature of this embodiment is that the zener breakdown voltage is easily adjusted by a simple modification to the fabrication process. The field plate creates two opposing junctions with the spacing determined by the field plate length.