A known problem when manufacturing transistors is the stress undesirably introduced by the spacers into the transistor channel region. In order to solve this problem, the present invention proposes an ion implantation aimed at relaxing the stress of the spacer materials. The relax implantation is performed after the spacer has been completely formed. The relax implantation may be performed after a silicidation process or after an implantation step in the source and drain regions followed by an activation annealing and before performing the silicidation process.