Selective tungsten CVD on submicron contact hole

This work investigates the deposition properties of selective chemically vapor-deposited tungsten for filling the deep sub-half micron contact holes using the process of silane reduction of tungsten hexafluoride. Low-resistivity tungsten with excellent selectivity and conformal coverage can be obtained with a SiH4/WF6 flow rate ratios less than 0.6 at deposition temperatures between 280 to 350 degrees C. Junction leakage and contact resistance of the AlSiCu/W/n(+)p and AlSiCu/W/p(+)n diodes as well as the electromigration properties of the AlSiCu/W/n(+)p structure were investigated.