Bi-directional epitaxial doping technique

摘要

A method of forming a semiconductor device on a substrate. The method includes forming a first epitaxial layer on the substrate. Next, a selected impurity is introduced to a surface of the first epitaxial layer. A second epitaxial layer is then formed on the surface of the first epitaxial layer and over the selected impurity. Finally, the selected impurity is driven through the first epitaxial layer and the second epitaxial layer to form the desired doped regions.