DOUBLE GRID AND DOUBLE WELL SUBSTRATE PLATE TRENCH DRAM CELL ARRAY

摘要

A high density substrate plate trench DRAM cell memory device and processare described in which a buried region (32) is formed adjacent to deep trenchcapacitors such that the substrate region of DRAM transfer FETs can be electricallyisolated from other FETs on a semiconductor substrate (10). The buried region (32)is partially formed by ion implantation and diffusion to intersect the walls of thedeep trenches (22). The buried region (32) is contacted along its perimeter by areach through region to complete the isolation. The combined regions reducecharge loss due to better control of device parasitics.