Patent ID: 6469325
Filing Date: 2002-10-22
Classification: H01L

Abstract:
A semiconductor integrated circuit device comprising,a protection element having a thyristor structure, which is electrically connected between an external terminal and a ground potential, said protection element being provided on a semiconductor substrate, and a diode serving as a protection element electrically connected between said external terminal and said ground potential so that said diode is connected in the forward direction when a negative overvoltage is applied to said external terminal wherein said protection element having the thyristor structure includes, a first semiconductor region of a conductivity type opposite to that of the semiconductor substrate, which is formed in the semiconductor substrate; a second semiconductor region of a conductivity type opposite to that of the semiconductor substrate, said second semiconductor region being formed in the semiconductor substrate so as to be spaced away from said first semiconductor region; a third semiconductor region corresponding to a region of conductivity type opposite to that of said first semiconductor region, said third semiconductor region being formed between at least said first semiconductor region and said second semiconductor region in the semiconductor substrate; a fourth semiconductor region formed within said first semiconductor region, constructed by a semiconductor region of the same conductivity type as that of said first semiconductor region and which is electrically connected to said external terminal; a fifth semiconductor region formed within said first semiconductor region so as to be adjacent to said fourth semiconductor region, constructed by a semiconductor region of a conductivity type opposite to that of said first semiconductor region and which is electrically connected to said external terminal; a sixth semiconductor region of the same conductivity type as that of said first semiconductor region, said sixth semiconductor region having one portion disposed in said first semiconductor region and the other portion disposed in a region between said first semiconductor region and said second semiconductor region; and a seventh semiconductor region having one portion disposed in said second semiconductor region and the other portion disposed in a region between said first semiconductor region and said second semiconductor region so as to be spaced away from said sixth semiconductor region, said seventh semiconductor region being constructed by a semiconductor region of the same conductivity type as that of said first semiconductor region and being electrically connected to said ground potential; said diode having an eighth semiconductor region of a conductivity type opposite to that of said first semiconductor region, said eighth semiconductor region being electrically connected to the ground potential and provided within said first semiconductor region.