A gate insulating film is formed in a first region and a second region of a substrate, a first metallic film is formed on the gate insulating film in one of the first region or the second region, and a second metallic film is formed on each of the first and second regions. Furthermore, a protective film is formed on the second metallic film, and the protective film and the metallic film are patterned to the pattern of the gate 
electrode. Next, a first sidewall is formed on the side of a gate 
electrode. Then, impurities producing first and second 
conductivity types are implanted into the surface of the substrate in respective regions, using the first sidewalls and the gate electrodes as masks to form a first 
impurity-diffused region, and impurities producing second and first 
conductivity types are implanted to form an 
impurity diffusion preventing layer. Thereafter, a second sidewall is formed on the side of the first sidewall, and an 
impurity is implanted into the surface of the substrate using the second sidewalls and the gate electrodes as masks to form a second impurity-diffused region.