The electrical characteristics of a WSichi contact electrode with a WSichi N diffusion barrier are evaluated. The WSichiN diffusion barrier was formed by WSi, surface nitridation using electron cyclotron resonance nitrogen plasma. It is found that the WSchiN layer prevents impurity diffusion from the diffusion layer into the WSi, electrode and the concentration of impurities at the interface between the diffusion layer and WSichiWSi2N/WSichi, electrode is over 1 x 10(20) atom/cm(3) even after rapid thermal annealing (RTA) at 1100 degrees C for 10 s. Moreover, the total resistance of both an n(+)-Si/WSichi/WSichiN/WSichi and p(+)-Si/WSichi/WSichiN/WSichi contact system, which is the sum of the electrode resistance and the contact resistance at the electrode/diffusion layer interface, decreases below one-fifteenth after RTA. The reduction of the total resistance by RTA is discussed.