METHODS FOR FORMING FINFETS WITH SELF-ALIGNED SOURCE/DRAIN

摘要

A method includes forming a gate stack to cover a middle portion of a semiconductor fin, and doping an exposed portion of the semiconductor fin with an n-type impurity to form an n-type doped region. At least a portion of the middle portion is protected by the gate stack from receiving the n-type impurity. The method further includes etching the n-type doped region using chlorine radicals to form a recess, and performing an epitaxy to re-grow a semiconductor region in the recess.