220 the first insulation layer 225 is an oxide layer for molding in order to define the height and the shape of the capacitor for example the first insulation layer may be formed up to the same height as the lower electrode of the capacitor the first insulation layer 225 and the etch stopper 220 define a lower electrode area 230 after etching to expose the contact plug 215 if forming the contact plug 215 of poly silicon a transition metal layer not shown such as titanium tantalum or tungsten is formed on the surface of the lower electrode area 230 and the first insulating layer 225 in the present embodiment a titanium layer is used as the transition metal layer and may be formed by cvd at about 600 to 650 u00b0 c also the transition metal layer may be formed to about 80 to 90 u00e5 after performing a thermal process on the transition metal layer a silicide layer 235 a is formed on the poly silicon contact plug 215 if the thermal process is performed in a nitrogen atmosphere the transition metal layer transforms into a metal nitride layer 235 b the metal nitride layer 235 b does not eliminate if the transition metal layer is thermal processed in another gas atmosphere the remaining transition metal layer can be eliminated referring to fig3 b a metal nitride layer 240 is formed on the lower electrode area 230 and the first insulation layer 225 as a lower electrode for example the metal nitride layer 240 may be a titanium.