JPS57192070A - Semiconductor memory unit - Google Patents

Abstract

PURPOSE:To enlarge intensity against radiation of alpha rays, etc., and to prevent the erroneous operation of a semiconductor memory unit by a method wherein specific resistance of a semiconductor substrate at the memory element part is reduced selectively than that at the circumferential circuit element part, and the extension of depletion layer at the memory element part is suppressed and junction capacity thereof is enlaged. CONSTITUTION:At a memory cell M-CEL of a dynamic RAM, for example, the low resistance P<+> type semiconductor region 2 having specific resistance 0.1- 1.0OMEGAcm is formed by the ion implantation technique, etc., on the one main face side of a single crystal Si substrate 1 having specific resistance 10OMEGAcm, and an N<+> type source region 3 and drain region 4, a polycrystalline Si gate electrode 5, and a capacitor CP formed by making a polycrystalline Si film 6 as an electrode on one side and moreover making a gate SiO2 film 7 as a dielectric film, are provided repsectively on the region 2 thereof. Specific resistance of substrate of the memory cell M-CEL is reduced by 1-2 figures than specific resistance of the substrate 1 by this way, and at the same time at the circumferential circuit element part, an MISFET QD is provided on the substrate 1 for driving and for input/output of the memory cell part.