Dynamic random access memory with improved contact arrangements

A dynamic random access memory (DRAM) having first MISFETs for selecting memory cells formed on the principal surface of a semiconductor substrate and second MISFETs for peripheral circuits formed on the surface, comprising:

• polycrystal silicon plugs formed in a first insulation film and arranged on one of the source/drain regions of each of the first MISFETs;
• bit lines arranged on a second insulation film and electrically connected to the respective polycrystal silicon plugs by way of respective contact holes formed to pass through the second insulation film arranged on the first insulation film;
• and
• wires of a first wiring layer arranged on the second insulation film and electrically connected to the source/drain regions of the second MISFETs respectively by way of second contact holes formed to pass through the first and second insulation films;
• wherein
• a silicide film of an element selected from titanium, tungsten and cobalt containing an impurity or impurities is formed in contact areas of the bit lines and the polycrystal silicon plugs;
• the impurity or impurities being one or more than one elements selected from nitrogen, oxygen, carbon and germanium.