SEMICONDUCTOR-CONTROLLED RECTIFIER FOR ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT

摘要

PURPOSE: A semiconductor-controlled rectifier is provided to reduce an occupying area of a well region by forming high density n-type and p-type impurity regions connected to an input/output pad in the well region and forming high density n-type and p-type impurity regions overlapping the well region. CONSTITUTION: A low density region of the second conductivity type is formed in a semiconductor substrate(101) of the first conductivity type. The first high density region(103) of the first conductivity type is formed in the low density region, connected to the first node. The second high density region(104) of the second conductivity type overlaps the low density region, connected to the first node. The third high density region(106) of the second conductivity type is formed in the substrate, adjacent to the second high density region. A gate electrode(107) is formed on the substrate between the second and third high density regions, electrically connected to the second node. The fourth high density region of the first conductivity type is formed in the substrate opposite to the second high density region, electrically connected to the second node. The fifth high density region of the second conductivity type is formed in the substrate between the low density region and the fourth high density region, electrically connected to the second node. The sixth high density region of the first conductivity type is formed in the substrate between the fifth high density region and the low density region, electrically connected to the third high density region.