Abstract: An integrated circuit structures such as an SRAM construction wherein the soft error rate is reduced comprises an integrated circuit structure formed in a semiconductor substrate, wherein at least one N channel transistor is built in a P well adjacent to one or more deep N wells connected to the high voltage supply and the deep N wells extend from the surface of the substrate down into the substrate to a depth at least equal to that depth at which alpha particle-generated electron-hole pairs can effectively cause a soft error in the SRAM cell. For a 0.25 &mgr;m SRAM design having one or more N wells of a conventional depth not exceeding about 0.5 &mgr;m, the depth at which alpha particle-generated electron-hole pairs can effectively cause a soft error in the SRAM cell is from 1 to 3 &mgr;m. The deep N well of the 0.25 &mgr;m SRAM design, therefore, extends down from the substrate surface a distance of at least about 1 &mgr;m, and preferably at least about 2 &mgr;m.