Method for improving narrow channel effect of n-type field effect transistor (NFET) by stress memorization technology

The invention relates to a method for improving a narrow channel effect of an n-type field effect transistor (NFET) by a stress memorization technology. The method is characterized by comprising the following steps of: providing a semiconductor substrate, and forming a semiconductor device having an NFET structure on the semiconductor substrate; depositing an etching stop layer on the semiconductor device; depositing a stress layer on the etching stop layer; performing ageing treatment on the semiconductor device with the formed etching stop layer and the stress layer; etching to remove the stress layer; performing a high temperature annealing step so as to activate doping of a source region and a drain region of the semiconductor device; and removing the etching stop layer. By the method, the stress layer is formed on the semiconductor device having the NFET structure, then is subjected to the ageing treatment, and is removed before a high temperature annealing process, so that an over-high stress effect of