Patent ID: 6424509
Filing Date: 2002-07-23
Classification: H01L

Abstract:
A semiconductor device including a power source wiring, a ground wiring and an input terminal supplied with an input signal from an external device and connected to internal circuits, comprising:a first semiconductor area of a first conductive type at a semiconductor substrate surface; a protective bipolar transistor having a collector area of a second conductive type, which is formed in the first semiconductor area of the first conductive type at the semiconductor substrate surface and connected to the input terminal and an emitter area of the second conductive type, wherein the emitter is formed in the first semiconductor area and connected to the ground wiring; a protective diode having an anode area of the first conductive type, which is formed in a second semiconductor area of the second conductive type at the semiconductor substrate surface and connected to the input terminal, the second semiconductor area being connected to the power source wiring as a cathode area; and a protective MOS transistor having a drain area of the second conductive type, which is formed in a third semiconductor area of the first conductive type at the semiconductor substrate surface and connected to the cathode area, a source area of the second conductive type, which is formed in the third semiconductor area and connected to the ground wiring, and a gate electrode, which is formed on the semiconductor substrate between the drain and source areas and connected to the ground wiring.