Semiconductor structure and manufacturing methods

Abstract

A method for fabricating a trench capacitor wherein the trench in the substrate. The walls of the trench are lined with a semiconductor material having a substantially uniform thickness over sidewalls of the trench, such trench being void of the material in an inner region of the trench. A dielectric collar is formed in an upper portion of the trench above the semiconductor material. The semiconductor material is removed from the bottom portion of the trench. A node dielectric is formed that lines the collar and trench sidewalls at the bottom portion of the trench. The trench is filed with a doped semiconductor material, such doped semiconductor material providing an electrode of the trench capacitor. The trench is forming includes forming the trench with a diameter of the lower portion of the trench effectively at least equal to about the upper portion of the trench.

Dependencies are inferred from the claim text.