| 摘要 |
PURPOSE:To protect the input pad side portion of a polycrystalline silicon resistor belonging to a MIS transistor input protecting circuit from disconnection due to electric field concentration attributable to an input surge voltage by a method wherein the polycrystalline silicon resistor is made larger in width at the portion nearer to the input pad. CONSTITUTION:The width of a polycrystalline silicon resistor 2 is 50mum near an input pad 1, which is reduced to 20mum and then to 5mum, as it is further from the input pad 1. The portion of the resistor 2 nearest to the input pad 1 is ten times bigger than the portion remotest from the input pad 1. The resistor 2 is designed to be especially bigger at a bend for reinforcement against the concentration of electric field attributable to such a bend. The resistor 2 is set to present a resistance value of not less than 600OMEGA. It is so designed that it withstands an input voltage measured approximately up to 30V at the end of the resistor 2 so that the drain junction in a protecting MIS transistor 4 may be protected from breakdown. Further, with the polycrystalline silicon resistor 2 being shaped wider toward the input pad 1, it is protected from disconnection due to electric field concentration at a location near the input pad 1 attributable to an input surge voltage. |
