in the nmos transistor alternatively the first metal containing layer pattern 311 may include one of a metal compound layer pattern and a metal layer pattern the first diffusion barrier layer 318 a is positioned on a sidewall of the first conductive layer pattern 320 a and the second diffusion barrier layer 319 a is located on a sidewall of the first metal containing layer pattern 311 the first diffusion barrier layer 318 a may prevent the impurities in the first conductive layer pattern 320 a from diffusing into the insulation layer 302 the substrate 300 and or a contact or a plug formed adjacent to the first electrode structure the second diffusion barrier layer 319 a may also prevent the diffusion of metal atoms from the first metal containing layer pattern 311 toward the insulation layer 302 the substrate 300 and or the contact or the plug formed adjacent to the first electrode structure the first second diffusion barrier layer 318 a and the second diffusion barrier layer 319 a may be generated from the first conductive layer pattern 320 a and the first metal containing layer pattern 311 respectively for example the first and the second diffusion barrier layers 318 a and 319 a may be.