WNx/W as a low-resistance gate material and local interconnect

Abstract

In this study we propose the use of an in-situ deposition of an interfacial WN, film to enable the use of W as a low resistance gate and local interconnect layer. We have found that the interfacial WN, layer greatly improves the adhesion and nucleation of the following W deposition. Furthermore, the interfacial WN, stabilizes the W to Si interface. preventing any silicide formation during anneals up to 850OC. The effect of the WN, interface layer was investigated by using a process split as shown infigure 1. The depositions were performed in the same process module with only a change in the recipe to either include, or exclude, the WN, deposition step. The composition of the WN, film was WNO and the thickness range investigated was from 50 to 200 A. Sheet resistance of the composite WN,N film is in the range of 1 to 2 ohms/square, depending on the thickness of WN, used.