High capacitance isolated surrounding stacked trench cell for advanced DRAMS

Abstract

High density trench type memory cells have been fabricated with silicon islands formed by a grid of trenches. The thin poly-silicon capacitor electrodes surround almost the total cell area and are isolated from the substrate. Due to the large capacitor area very high cell capacitances can be achieved which makes this cell concept shrinkable up to the 256M-DRAM generation.