Abstract
A method of forming an integrated circuit includes forming a gate structure over a substrate. Portions of the substrate are removed to form recesses adjacent to the gate structure. A dopant-rich layer having first type dopants is formed on a sidewall and a bottom of each of the recesses. A silicon-containing material structure is formed in each of the recesses. The silicon-containing material structure has second type dopants. The second type dopants are opposite to the first type dopants.