Semiconductor integrated circuit

Abstract

Abstract PURPOSE:To improve electrostatic breakdown voltage even though the occupying area of an input protecting circuit on a chip is small, by connecting an MOS transistor as an input protecting element between an input wiring end a specified potential end, forming a gate electrode so as to surround the drain of the transistor, and connecting the electrode to the specified potential end. CONSTITUTION:An MOS transistor 3 is connected to at least one of the parts between an input wiring 2 and a first power source potential end or between the input wiring 2 and a second power source potential end, whose potential is higher than the first power source potential end, as an input protecting circuit. In this structure of the MOS transistor 3, a gate electrode is formed so as to surround a drain, and the electrode is connected to the same potential end as a source. When an excessive voltage is inputted, a current flows through a diode at the junction between the drain of the MOS transistor 3 and a semiconductor substrate. A current flows through a parasitic bipolar transistor 4, which is present between the source and the drain of the MOS transistor 3. Thus the current flowing into the substrate is decreased to a large extent. The risk of the electrostatic breakdown at an input gate 5 triggered by the current becomes extremely small.

Inventors

• 👤 Hideo Sakai
• 👤 酒井　日出男
• 👤 Kazuyuki Uchida
• 👤 内田　和幸
• 👤 Yukihiro Saeki
• 👤 佐伯　幸弘

Bibliographic Details