A semiconductor device having an electrode with reduced electrical contact resistance even where either electrons or holes are majority carriers is disclosed. This device has an n-type diffusion layer and a p-type diffusion layer in a top surface of a semiconductor substrate. The device also has first and second metal wires patterned to overlie the n-type and p-type diffusion layers, respectively, with a dielectric layer interposed therebetween, a first contact electrode for electrical connection between the n-type diffusion layer and the first metal wire, and a second contact electrode for connection between the p-type diffusion layer and the second metal wire. The first contact electrode's portion in contact with the n-type diffusion layer and the second contact electrode's portion contacted with the p-type diffusion layer are each formed of a first conductor that contains a metal and a second conductor containing a rare earth metal.