A method for manufacturing a semiconductor element is provided. The method includes a first silicon region, a second silicon region, and a metal silicide layer, wherein the metal silicide layer contacts with the first silicon region and the second silicon region separately, the method including steps of performing a first doping process to dope an N-type dopant into the first silicon region and to dope a diffusion barrier impurity into a portion of the metal silicide layer contacting with the first silicon region, and performing a second doping process to dope a P-type dopant into the second silicon region and to dope a diffusion barrier impurity into a portion of the metal silicide layer contacting with the second silicon region.