Importance

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Abstract

A contact for a semiconductor device has a via extending through a dielectric and collimated titanium in the via. Depositing titanium by collimation places sufficient metal into high aspect ratio contacts to make good electrical connection. The collimated titanium may be reacted in a nitrogen containing ambient to form a titanium silicide layer at the bottom of the contact and a titanium nitride layer over the titanium silicide layer. The titanium silicide layer provides good electrical contact to a device in a silicon semiconductor substrate and lowers contact resistance. Tungsten may be deposited over the colliminated titanium to form a conductor layer. The titanium nitride layer provides a sticking layer for the tungsten. The contact structure and the method are useful in high aspect ratio contacts present in VLSI multilevel interconnected devices such as dynamic random access memories.

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First Claim