film 32 a fabrication method for the capacitor shown in fig5 is described using fig6 to 16 first a contact hole 91 is bored through the interlayer insulating film 21 fig6 after the contact hole 91 is buried with a polysilicon film the polysilicon film is etched back to form the polysilicon plug 11 fig7 a titanium silicide film 31 as a contact metal film and a titanium nitride film 32 as a barrier metal film are formed on the recessed portion of the top surface of the polysilicon plug 11 fig8 in order to form the titanium silicide film 31 a titanium film of 10 nm thick is deposited on the hole by sputtering after which a titanium silicide film is formed at the recessed bottom portion by a heat treatment in a nitrogen atmosphere at 700 u00b0 c and the titanium film on the recessed side portion is transformed to a titanium nitride film at the same time the reason why the titanium film on the recessed side portion is transformed to the titanium nitride film is to prevent the titanium film from being oxidized in the later oxidization of the tantalum oxide film the titanium film is oxidized very easily as compared with the titanium nitride film subsequently the barrier metal film outside the recess is removed by cmp chemical mechanical polishing fig9 next the interlayer insulating film 22 is formed and a cylinder hole.