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Abstract

A method is disclosed for providing a self-aligned silicide strap for connecting thin polysilicon layers (poly-1 and poly-2, etc.) separated by non-conducting gaps. A butting contact opening to the layers is formed in an overlying insulating layer. The contact exposes the poly-1 and poly-2 layers. A thin polysilicon layer (poly-3) is then deposited over the insulating layer and into the contact. This is followed by deposition of a refractory metal layer. The poly-3 layer should be thin enough that, alone, it cannot supply enough silicon to support full silicidation of the refractory metal layer. The structure is next sintered so that a silicide strap is formed in the contact opening and across exposed portions of the poly-1 and poly-2 layers. The ratio of silicon to titanium in regions over the insulating layer is lower than that in the strap, such that these more metallic regions may be selectively removed. The preferred embodiment simultaneously provides cladding of device active areas, the silicon added by poly-3 serving to reduce spiking into the active areas.

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First Claim