Semiconductor device with a silicide layer

A field effect transistor comprising:

• a semiconductor substrate of a first conductive type;
• a gate oxide film formed on a principal surface of said semiconductor substrate;
• a gate electrode formed on an upper surface of said gate oxide film,
• source/drain diffusion layers of a second conductive type formed by injecting ions in said principal surface of said semiconductor substrate;
• a silicide layer of a metal as a non-reducing diffusion seed formed in said gate electrode;
• an other silicide layer of a metal as said non-reducing diffusion seed formed in said source/drain diffusion layers;
• an impurity layer distributed inside said silicide layer and said gate electrode, said impurity layer consisting essentially of an element smaller in activation energy than said ions;
• and
• an other impurity layer distributed inside said other silicide layer and said source/drain diffusion layers, said other impurity layer consisting essentially of said element.

A field effect transistor comprising:

• a silicon substrate of first conductive type;
• a gate oxide film formed on a principal surface of said silicon substrate;
• a gate electrode formed on an upper surface of said gate oxide film;
• source/drain diffusion layers of a second conductive type formed by injecting ions into said principal surface of said silicon substrate;
• a silicide layer of a metal as a non-reducing diffusion seed formed in said gate electrode;
• an other silicide layer of a metal as said non-reducing diffusion seed formed in said source/drain diffusion layers;
• a nitrogen layer distributed inside said silicide layer and said gate electrode, said nitrogen layer having a density in a range from 1E16/cm.sup.3 to 1E20/cm.sup.3 ;
• and
• an other nitrogen layer distributed inside said other silicide layer and said source/drain diffusion layers, said other nitrogen layer having a density in a range from 1E16/cm.sup.3 to 1E20/cm.sup.3.