MOS TRANSISTOR OF ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT

摘要

PURPOSE: A MOS transistor of ESD(electrostatic discharge) is provided to improve tolerance of ESD by connecting Vss to outermost gate electrode using finger-type NMOS. CONSTITUTION: A finger-type NMOS transistor is arranged by electrode structure of gate(21)/drain(25)/gate(21)/ source(23)/gate(21)... without an outermost source electrode(23). An internal circuit(27) is connected to the gate electrodes(21). The outermost gate electrode(21) is grounded to Vss. Thereby, over-current applied to the outermost gate electrode(21) is dispersed by total gate electrodes, so that a rupture of gate oxide is prevented and the tolerance of ESD is increased.