Patent ID: 6825504
Filing Date: 2004-11-30
Classification: H01L

Abstract:
A semiconductor integrated circuit device comprising:a protection element having a thyristor structure, which is electrically connected between a first external terminal for receiving a signal and a second external terminal to be coupled to a fixed potential, said protection element being provided on a semiconductor substrate; and a diode serving as a protection element electrically connected between said first external terminal and said second external terminal so that said diode is connected in the forward direction when a negative overvoltage is applied to said first external terminal, wherein said thyristor structure includes: a first semiconductor region of a first conductivity type formed in the semiconductor substrate; a second semiconductor region of a second conductivity type opposite to that of said first semiconductor region, said second semiconductor region being formed in the semiconductor substrate so as to be adjacent to said first semiconductor region; a third semiconductor region of said second conductivity type formed within said first semiconductor region and electrically connected to said first external terminal, and a fourth semiconductor region of said first conductivity type formed within said second semiconductor region and electrically connected to said second external terminal, wherein said diode includes: a fifth semiconductor region of said first conductivity type formed within said first semiconductor region and electrically connected to said first external terminal; and a sixth semiconductor region of said second conductivity type formed within said first semiconductor region and electrically connected to said second external terminal, wherein the semiconductor integrated circuit device further includes a seventh semiconductor region of said first conductivity type formed within said first semiconductor region and extending into said second semiconductor region, said seventh semiconductor region having a higher impurity concentration than that of said first semiconductor region.