| 摘要 |
PURPOSE:To evade a decrease in dielectric strength by making the dielectric strength of a protective diode higher than that of an IGFET, by providing the PN junction of the protective diode deeply when providing the IGFET and protective diode for it to the same semiconductor substrate. CONSTITUTION:In N<->-type Si substrate 1, P-type base region 2 is formed by diffusion and into it, N-type source region 3 is provided; and channel part C is made of them and SiO2 gate insulation layer is adhered to its surface, thereby obtaining an IGFET. Next, P<->-type region 14 is of the same P type, but formed by diffusion more deeply than region 2 besides region 2, P-type regions 15 and 16 are provided into it, and N<+>-type region 17 in region 15 and N<+>-type region 18 in region 16 are formed by diffusion respectively to constitute a protective diode. In this way, since the depth of junction Js produced in the protective diode is made deeper than that of PN junction J of the FET, the dielectric strength of Js becomes higher than that of J and even if the protective diode is provided into the same substrate, the dielectric strength of the FET is not caused to decrease. |
