Patent ID: 7190027

Claim:
A semiconductor device comprising: a semiconductor substrate; a low concentration region disposed in the substrate and including a first conductivity type impurity with a low impurity concentration; an intermediate concentration region disposed in the low concentration region and including the first conductivity type impurity with an intermediate impurity concentration; a first electrode region disposed in the intermediate concentration region and including the first conductivity type impurity with a high impurity concentration; and a second electrode region disposed in the low concentration region and including the first conductivity type impurity with an impurity concentration different from the low impurity concentration of the low concentration region, wherein the low concentration region and the intermediate concentration region provide a first boundary therebetween, wherein the intermediate concentration region and the first electrode region provide a second boundary therebetween, wherein the device has a current-voltage characteristic associated with a predetermined relationship between a current in the first electrode region and a voltage between the first and second electrode regions, wherein the current-voltage characteristic includes a first break point attributed to the first boundary and a second break point attributed to the second boundary, wherein the first break point has a voltage, which is equal to or smaller than another voltage of the second break point, wherein the device has a maximum current density flowing between the first and second electrode regions when the device is applied with an electrostatic discharge surge, wherein the first break point has a current density, which is smaller than the maximum current density, and wherein the second break point has another current density, which is larger than the maximum current density.