Patent ID: 8865550

Claim:
A method of forming a buried bit line, comprising: providing a substrate, wherein a line-shaped trench region is defined in the substrate; forming a line-shaped trench in the line-shaped trench region of the substrate, wherein the line-shaped trench comprises a sidewall surface and a bottom surface; widening the bottom surface of the line-shaped trench to form a curved bottom surface in the line-shaped trench; forming a doping area in the substrate adjacent to the curved bottom surface; and forming a buried conductive layer on the doping area such that the buried conductive layer forms the buried bit line, wherein the step of forming the buried conductive layer comprises: depositing a metal layer into the line-shaped trench; removing the doping area and the metal layer in the line-shaped trench region; and filling the line-shaped trench with an insulation material.