A semiconductor structure and fabrication method are provided. The method includes: providing a base substrate; forming doped epitaxial layers in the base substrate on sides of a gate structure on the base substrate; forming an interlayer dielectric layer over the base substrate and above the doped epitaxial layers; forming a contact opening in the interlayer dielectric layer; forming a dielectric layer on and surrounding each doped epitaxial layer; applying a repairing process on the dielectric layer; after the repairing process, forming a metal layer on the dielectric layer; and after forming the metal layer in the contact opening, forming a conductive plug in the contact opening.