Trench memory cells with buried isolation collars, and methods of fabricating same

摘要

The present invention relates to semiconductor devices, preferably dynamic random access memory (DRAM) cells, each of which contains at least one trench capacitor with a buried isolation collar. The trench capacitor is located in a trench in a semiconductor substrate, and it comprises inner and outer electrodes and a dielectric layer. The buried isolation collar is recessed into a sidewall of the trench and has a substantially uniform thickness. Such a buried isolation collar is preferably formed by oxygen implantation before trench etching.