| 摘要 |
PURPOSE:To improve the breakdown resistance of an input protecting circuit against an overvoltage in an IC having an input protecting circuit by enhancing an P-N junction withstand voltage between a resistor near the connection unit of wirings extending from an external terminal, to which an unexpected overvoltage is applied to a resistor, and semiconductor substrate. CONSTITUTION:An IC is formed of a P<-> type semiconductor substrate 4 formed of silicon single crystal and having an impurity density, for example, of 1X10<15> (atoms/cm<3>), an N<-> type semiconductor region 32 is a connection unit of an external terminal 9 and a resistor 10, connected to the resistor 10, and provided on a main surface of a semiconductor substrate 4 to cover it. The impurity density of this N<-> type semiconductor region is low in the degree, for example, of 1X10<16> (atoms/cm<3>). Since the elongation of a depletion layer formed of a P-N junction of the region 32 and the substrate 4 is larger than that of the depletion layer formed of a P-N junction of the resistor 10 and the substrate 4, the breakdown resistance of the resistor 10 against the overvoltage for causing an electrostatic breakdown is improved in the connection unit of the terminal 9 to the resistor 10. |
