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- We perform the physical analysis such that Si/W composition ratios and phosphorus distribution change in the WSix thin films according to phosphorus concentration of polysilicon and WF6 flow rate for the formation of WSix polycide used as a gate electrode. We report that these physical characteristics have effects on the contact resistance between word line and bit line in DRAM devices. RBS measurements show that for the samples having phosphorus concentrations of 4.75 and 6.0×1020 atoms/cm3 in polysilicon, by applying WF6 flow rates decreases from 4.5 to 3.5 sccm, Si/W composition ratio has increases to 2.05∼2.24 and 2.01∼2.19, respectively. SIMS analysis give that phosphorus concentration of polysilicon for both samples have decreases after annealing, but phosphorus concentration of WSix thin film has increases by applying WF6 flow rates decreases from 4.5 to 3.5 sccm. The contact resistance between word line and bit line in the sample with phosphorus concentration of 6.0×1020 atoms/cm3 in polysilicon is lower than the sample with 4.75×1020 atoms/cm3. After applying WF6 flow rates decreases from 4.5 to 3.5 sccm, the contact resistance has been improved dramatically from 10.1 to 2.3μΩ-cm2.