Patent ID: 6235610
Filing Date: 2001-05-22
Classification: H01L

Abstract:
A process for selectively introducing a dopant into a bottom of a trench in a semiconductor material layer, the trench having sloped side walls and a bottom wall, the process comprising the steps of:depositing a nonconformal barrier layer adjacent the semiconductor material layer to form a deposited barrier layer having a first thickness over a planar surface of the semiconductor material layer, a second thickness less than the first thickness over the bottom wall of the trench, and a thickness over the sloped side walls of the trench decreasing from the first thickness to the second thickness; andimplanting a dopant through the deposited barrier layer and into the semiconductor material layer using the nonconformal deposited barrier layer as an implant mask, the dopant implanted in the semiconductor material layer corresponds to at least a width of the bottom wall of the trench.