the drain extension 32 and source extension 42 are covered by a gate oxide layer 54 and a gate 56 the drain and source extensions 32 and 42 are laterally bounded by field oxide regions 60 and covered by an insulation layer 62 the source lead 48 and the gate 56 are preferably all coupled to the ground and in some embodiments the substrate 25 is also coupled to ground although shown formed in a p type substrate 6 another embodiment of the invention could be formed in an n type substrate by switching the dopant types of the substrate and components as is known in the art the operation of the protection circuit 22 during a positive esd event will now be explained with reference to fig3 a rising voltage travels from a pin through the drain lead 46 and increases until a trigger voltage level of the protection circuit 22 is reached when the trigger voltage is reached avalanche breakdown causes charge to flow from the drain 30 and the drain extension 32 into the substrate 25 since the drain extension 32 has a lower doping level than the drain 30 more resistance is presented to the current traveling through that portion consequently the more resistive drain extension 32 channels more charge to flow from the drain 30 into the substrate 25 and thus less charge flows from the drain extension 32 into the substrate 25 charge crowding is minimized in the structure shown in.