| 摘要 |
PURPOSE:To simplify manufacturing process without decreasing electrostatic breakdown voltage, by employing a double diffused drain structure for a clamp MOS element in electrostatic protecting circuit as well as for the MOS element in an internal circuit. CONSTITUTION:A substrate 10 is provided with the MOS element in an internal circuit 20 and with an input diffused resistor and a clamp MOS element in an electrostatic protecting circuit 30. The high concentration of B is implanted in the internal circuit 20 which has a double diffused drain structure consisting of an N<+> diffused layer 201 implanted with As and an N<-> diffused layer 202 implanted with P. The electrostatic protecting circuit 30 has the double diffused drain structure consisting of N<+> diffused layers 301 and 302 implanted with As and N<-> diffused layers 303 and 304 implanted with P, in which the As and the P are implanted simultaneously. No photoresist process is required for providing a single diffused drain structure in the electrostatic protecting circuit. Thus, the manufacturing process can be simplified while the electrostatic breakdown voltage is improved. |
