DRAM cell capacitor having increased trench capacitance

A trench capacitor comprising a first trench adjacent a second trench in a substrate, said substrate having a surface, each of said trenches having a top on said surface, a bottom in said substrate, and opposing inner and outer side walls extending from said top to said bottom, wherein the inner wall of said first trench electrically contacts the inner wall of said second trench, and wherein said opposing side walls in at least one of said trenches curve away from each other from top to bottom.

A trench capacitor comprising a first trench adjacent a second trench in a substrate, said substrate having a surface, each of said trenches having a top on said surface, a bottom in said substrate, and opposing inner and outer side walls extending from said top to said bottom, wherein the inner wall of said first trench electrically contacts the inner wall of said second trench, and wherein said opposing side walls in at least one of said trenches curve in opposite directions and reach a maximum distance from each other at a point intermediate the top and bottom of said trench.

A trench capacitor comprising a first trench adjacent a second trench in a substrate, said substrate having a surface, each of said trenches having a top on said surface, a bottom in said substrate, and opposing inner and outer side walls extending from said top to said bottom, wherein the inner wall of said first trench electrically contacts the inner wall of said second trench, and wherein at least one of said trenches is curved around an axis substantially perpendicular to the substrate surface.

A trench capacitor comprising a trench in a substrate, said substrate having a surface, wherein the trench is curved around an axis substantially perpendicular to the substrate surface, said trench having a top on said surface, a bottom in said substrate and opposing inner and outer side walls extending from said top to said bottom, curving in opposite directions, and reaching a maximum distance from each other at a point intermediate the top and bottom of said trench.

A trench capacitor comprising a trench in a substrate, said substrate having a surface, wherein the trench is curved around an axis substantially perpendicular to the substrate surface, said trench having a top on said surface, a bottom in said substrate and opposing inner and outer side walls extending from said top to said bottom with said inner side walls physically contacting.